OpenSource Hardware is a trend in recently life or we could say, it is old fashion way. I am glad to find it makes the world better.

But NOW I must talk on a serious topic: Why NOT Open Source Hardware?

Somebody may ask, is VoCore an open source hardware?
Not at all, please give me five minutes to explain.

How to define an open source hardware?
First, let’s check open source software:
They are totally free to use, everybody could modify it, contribute to it, once you have the source code, it is totally under your control.

You might say, I cloned the Arduino from scratch, even from a hand-making PCB, and everything just works well;
Ye, you are right, you made one open source hardware. But I have to say, Arduino is very simple that is why you can make it.

Here is a true story.

A student from India contact me, he want to make some copys to lower the cost, I think it is a good start of the open source hardware, so I spend a lot of time and tried my best to help him but fail at final…After a lot of work, he finally make some copy, but its cost is 3 times than current VoCore2… Of course for fun it worth. 🙂 And I recognize VoCore2 should not be open source:

1. PCB quality is important, for example, at solder layer it even covers the metal pad, it should be NG in most factory but cheap PCB provider do not care that. It will increase cost for the low yield rate.
2. The impedance matching, cheap PCB provider do not have that. That will effect RF, USB and DDR, sometimes it will slow down data transfer speed, sometimes it can not work at all.
3. SMT quality, cheap factory uses cheap machine, increase cost because low yield rate.
4. Low quality chips. Some chips are incredible low price, the small batch even lower than mass order especially on alibaba & 1688 & taobao), the recycle ones normally are from junks, the chips’ pads are oxidized, maybe pass test in factory but once you use it with heavy load, the heat will broke them. For my production, must and only use new chips(out of chip factory < six months with vacuum packaging) from the top provider or directly from its maker.

PS: that’s why a lot of cheap production from ShenZhen only have a short life. That is very very bad and dishonest.

And many many details are not in books and hard to show in blog, they are the experience of an engineer.

That is still NOT the end…opensource hardware do not include:

• get contact with good providers(digikey and mouser do not have everything)
• a test application to test the production
• a test jig to test the production
• calibrate the RF, need special device and application
• Not Good production, need to repair.

PS: every steps cost a lot of time + money.

That’s Why NOT Open Source Hardware:

A REAL COMPLEX hardware can not be simply open source as software, it is an art of production,  need time to try, to make mistake, need a lot of sweat and not a simple copy&paste.

I just want to public SCH and PCB could help people understand how it works, makes it easy to develop daughter board base on it, but not suggest directly copy from it.

ONE THING FOR SURE: VoCore and VoCore2 are ALWAYS OPEN, but never an open source hardware.

Coming soon, this June 🙂

## Interfaces:

1. export all GPIOs. (around 30)
2. export 3x UARTs.
3. export 1x I2C.
4. export 1x I2S.
5. export 1x reference clock.
6. export 1x USB 2.0.
7. export 1x PCIe 1.1
8. export 1x high speed SPI (max to 40Mbps)
9. export 2x antenna (UL.F) for 802.11n (max to 300Mbps)
10. input 3.6~6.0V, output 1.8V, 3.3V.
11. export 2x 10/100 ethernet port.
12. export 1x SDXC (allow high speed SD/TF card)
13. export 1x SPI slave
14. export 2x PWM (hardware PWM)

## Parameters:

* CPU: 580MHz MIPS.
* RAM: 64MB/128MB.(two versions, bigger memory special for who love python 🙂 )
* ROM: 16MB NOR FLASH.
* NORMAL POWER CONSUME: 74mA/5V (wifi on, no data transfer)
* PEAK POWER CONSUME: 233mA/5V (max speed cpu and wireless)

## Compare with VoCore v1.0:

* faster cpu speed.
* bigger RAM.
* lower power consume.
* better wifi signal.
* more interfaces.

We are busy on preparing the mass production, fixing & updating necessary drivers; preorder chips; prepare test process for factory; product the beta version…etc, many works left to do.
Planing stop making VoCore at May, focus on better version VoCore2.
Once June released the mass production, we will focus on software part. Anyway, VoCore is always a geek’s toy.

Now uboot part works, we need to make openwrt serial also output to UART2.

PS: weird issue, I find /dev/mem gone…is Linux 4.4.6 removed it?

My code based on trunk@49094. It is a develop openwrt version also contains many bugs. 🙂 If my code works please help me commit to openwrt.

If we do not modify anything, just flash uboot firmware to VoCore2, the serial log will end here.

U-Boot 1.1.3 (Mar 28 2016 - 22:54:05)

Board: Ralink APSoC DRAM:  64 MB
relocate_code Pointer at: 83fb8000
******************************
Software System Reset Occurred
******************************
flash manufacture id: c8, device id 40 18
find flash: GD25Q128C
*** Warning - bad CRC, using default environment

============================================ 
Ralink UBoot Version: 4.3.0.0
-------------------------------------------- 
ASIC 7628_MP (Port5<->None)
DRAM component: 512 Mbits DDR, width 16
DRAM bus: 16 bit
Total memory: 64 MBytes
Flash component: SPI Flash
Date:Mar 28 2016  Time:22:54:05
============================================ 
icache: sets:512, ways:4, linesz:32 ,total:65536
dcache: sets:256, ways:4, linesz:32 ,total:32768 

 ##### The CPU freq = 575 MHZ #### 
 estimate memory size =64 Mbytes
RESET MT7628 PHY!!!!!!
Please choose the operation: 
   1: Load system code to SDRAM via TFTP. 
   2: Load system code then write to Flash via TFTP. 
   3: Boot system code via Flash (default).
   4: Entr boot command line interface.
   7: Load Boot Loader code then write to Flash via Serial. 
   9: Load Boot Loader code then write to Flash via TFTP. 
 0 
   
3: System Boot system code via Flash.
## Booting image at bc050000 ...
   Image Name:   MIPS OpenWrt Linux-4.4.6
   Image Type:   MIPS Linux Kernel Image (lzma compressed)
   Data Size:    1270118 Bytes =  1.2 MB
   Load Address: 80000000
   Entry Point:  80000000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK
No initrd
## Transferring control to Linux (at address 80000000) ...
## Giving linux memsize in MB, 64

Starting kernel ...

[    0.000000] Linux version 4.4.6 (vocore@ubuntu) (gcc version 5.3.0 (OpenWrt GCC 5.3.0 r49094) ) #7 Fri Apr 1 18:35:11 UTC 2016
[    0.000000] Board has DDR2
[    0.000000] Analog PMU set to hw control
[    0.000000] Digital PMU set to hw control
[    0.000000] SoC Type: MediaTek MT7628AN ver:1 eco:2
[    0.000000] bootconsole [early0] enabled
[    0.000000] CPU0 revision is: 00019655 (MIPS 24KEc)
[    0.000000] MIPS: machine is VoCore2 64MB
[    0.000000] Determined physical RAM map:
[    0.000000]  memory: 04000000 @ 00000000 (usable)
[    0.000000] Initrd not found or empty - disabling initrd
[    0.000000] Zone ranges:
[    0.000000]   Normal   [mem 0x0000000000000000-0x0000000003ffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000000000-0x0000000003ffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x0000000003ffffff]
[    0.000000] Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
[    0.000000] Primary data cache 32kB, 4-way, PIPT, no aliases, linesize 32 bytes
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 16256
[    0.000000] Kernel command line: console=ttyS0,57600 rootfstype=squashfs,jffs2
[    0.000000] PID hash table entries: 256 (order: -2, 1024 bytes)
[    0.000000] Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
[    0.000000] Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Writing ErrCtl register=00073670
[    0.000000] Readback ErrCtl register=00073670
[    0.000000] Memory: 60844K/65536K available (2859K kernel code, 132K rwdata, 692K rodata, 148K init, 195K bss, 4692K reserved, 0K cma-reserved)
[    0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] NR_IRQS:256
[    0.000000] intc: using register map from devicetree
[    0.000000] add clock for 10000d00.uart1, rate = 40000000
[    0.000000] add clock for 10000e00.uart2, rate = 40000000
[    0.000000] add clock for cpu, rate = 580000000
[    0.000000] add clock for 10000100.timer, rate = 40000000
[    0.000000] add clock for 10000120.watchdog, rate = 40000000
[    0.000000] add clock for 10000b00.spi, rate = 193333333
[    0.000000] add clock for 10000b40.spi, rate = 193333333
[    0.000000] add clock for 10000c00.uartlite, rate = 40000000
[    0.000000] add clock for 10180000.wmac, rate = 40000000
[    0.000000] CPU Clock: 580MHz
[    0.000000] clocksource_probe: no matching clocksources found
[    0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 6590553264 ns
[    0.000011] sched_clock: 32 bits at 290MHz, resolution 3ns, wraps every 7405115902ns
[    0.015349] Calibrating delay loop... 385.84 BogoMIPS (lpj=1929216)
[    0.080520] pid_max: default: 32768 minimum: 301
[    0.089782] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.102736] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.122279] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.141778] pinctrl core: initialized pinctrl subsystem
[    0.152723] NET: Registered protocol family 16
[    0.179323] mt7621_gpio 10000600.gpio: registering 32 gpios
[    0.190412] mt7621_gpio 10000600.gpio: registering 32 gpios
[    0.201416] mt7621_gpio 10000600.gpio: registering 32 gpios
[    0.213941] clocksource: Switched to clocksource MIPS
[    0.225338] NET: Registered protocol family 2
[    0.234765] TCP established hash table entries: 1024 (order: 0, 4096 bytes)
[    0.248470] TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
[    0.260983] TCP: Hash tables configured (established 1024 bind 1024)
[    0.273632] UDP hash table entries: 256 (order: 0, 4096 bytes)
[    0.285086] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
[    0.297732] NET: Registered protocol family 1
[    0.307657] futex hash table entries: 256 (order: -1, 3072 bytes)
[    0.338516] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[    0.349983] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[    0.372014] io scheduler noop registered
[    0.379693] io scheduler deadline registered (default)
[    0.390672] Serial: 8250/16550 driver, 2 ports, IRQ sharing disabled
[    0.404112] rt2880-pinmux pinctrl: invalid group "spis" for function "pwm"
[    0.417827] console [ttyS0] disabled
[    0.424820] 10000e00.uart2: ttyS0 at MMIO 0x10000e00 (irq = 30, base_baud = 2500000) is a 16550A
[    0.442151] console [ttyS0] enabled
[    0.442151] console [ttyS0] enabled
[    0.455889] bootconsole [early0] disabled
[    0.455889] bootconsole [early0] disabled
[    0.473336] spi-mt7621 10000b00.spi: sys_freq: 193333333
[    0.487529] m25p80 spi32766.0: using chunked io (size=32)
[    0.498290] m25p80 spi32766.0: gd25q128 (16384 Kbytes)
[    0.508501] 4 ofpart partitions found on MTD device spi32766.0
[    0.520053] Creating 4 MTD partitions on "spi32766.0":
[    0.530233] 0x000000000000-0x000000030000 : "u-boot"
[    0.541846] 0x000000030000-0x000000040000 : "u-boot-env"
[    0.554307] 0x000000040000-0x000000050000 : "factory"
[    0.566168] 0x000000050000-0x000000800000 : "firmware"
[    0.603038] 2 uimage-fw partitions found on MTD device firmware
[    0.614797] 0x000000050000-0x0000001861a6 : "kernel"
[    0.626261] 0x0000001861a6-0x000000800000 : "rootfs"
[    0.637985] mtd: device 5 (rootfs) set to be root filesystem
[    0.649351] 1 squashfs-split partitions found on MTD device rootfs
[    0.661606] 0x000000370000-0x000000800000 : "rootfs_data"
[    0.683669] rt3050-esw 10110000.esw: link changed 0x00
[    0.695347] mtk_soc_eth 10100000.ethernet: generated random MAC address fe:67:bf:04:9d:38
[    0.712449] mtk_soc_eth 10100000.ethernet eth0: mediatek frame engine at 0xb0100000, irq 5
[    0.729378] mt7621_wdt 10000120.watchdog: Initialized
[    0.740958] NET: Registered protocol family 10
[    0.753409] NET: Registered protocol family 17
[    0.762371] bridge: automatic filtering via arp/ip/ip6tables has been deprecated. Update your scripts to load br_netfilter if you need this.
[    0.787379] 8021q: 802.1Q VLAN Support v1.8

Now my fix( as dirty as always 😀 )
1. modify MIWIFI-NANO.dts(I did not create new VoCore2.dts to make test easier)

+++ b/target/linux/ramips/dts/MIWIFI-NANO.dts
@@ -3,11 +3,11 @@
 /include/ "mt7628an.dtsi"
 
 / {
-       compatible = "xiaomi,MiWifi Nano", "mediatek,mt7628an-soc";
-       model = "MiWiFi Nano";
+       compatible = "vocore2,vocore", "mediatek,mt7628an-soc";
+       model = "VoCore2 64MB";
 
        chosen {
-               bootargs = "console=ttyS0,115200";
+               bootargs = "console=ttyS0,57600";
        };
 
        memory@0 {
@@ -18,7 +18,7 @@
        pinctrl {
                state_default: pinctrl0 {
                        gpio {
-                               ralink,group = "refclk", "wled", "gpio";
+                               ralink,group = "refclk", "gpio";
                                ralink,function = "gpio";
                        };
                };
@@ -87,5 +87,13 @@
                                };
                        };
                };
+
+               uart2@e00 {
+                        status = "okay";
+               };
+
+               pwm@5000 {
+                        status = "okay";
+               };
        };
 };

diff --git a/target/linux/ramips/dts/mt7628an.dtsi b/target/linux/ramips/dts/mt7628an.dtsi
index e120e56..819ac82 100644
--- a/target/linux/ramips/dts/mt7628an.dtsi
+++ b/target/linux/ramips/dts/mt7628an.dtsi
@@ -170,6 +170,8 @@
 
                        pinctrl-names = "default";
                        pinctrl-0 = <&uart0_pins>;
+
+                       status = "disabled";
                };
 
                uart1@d00 {
@@ -301,8 +303,8 @@
 
                uart2_pins: uart2 {
                        uart2 {
-                               ralink,group = "uart2";
-                               ralink,function = "uart2";
+                               ralink,group = "spis";
+                               ralink,function = "pwm";
                        };
                };

2. modify /linux-4.4.6/arch/mips/ralink/mt7620.c:407

		ralink_clk_add("10000d00.uartlite", periph_rate);
		ralink_clk_add("10000e00.uartlite", periph_rate);

change to

		ralink_clk_add("10000d00.uart1", periph_rate);
		ralink_clk_add("10000e00.uart2", periph_rate);

This just works, but I do not think it is the best way. We should use ttyS2 in dts, but not ttyS0. I still need time to understand how pinctrl works. 🙂