Pin share or I call it pinmux, it is a common feature of most MCU chips. Normally a pin we can use it as GPIO or some special functions.

In picture, the orange number is each pins GPIO number. And in the color block, there is its special function.

Here is a table from vocore.io/v2.html, for example, the pin 29 on the chip has three functions, one is used as GPIO, one is system reference clock, final one is SDcard CLK.

Left	Name	Mux	Note
–	+3.3VO	+3.3V output	max output current 100mA
30	TXD0	GPIO12, UART0 Lite TXD	pull down to GND, Test/Normal mode pin.
31	RXD0	GPIO13, UART0 Lite RXD	3.3V
29	REFCLK	GPIO11, reference clock, SDXC CLK*
33	P0RP	10/100 PHY Port #0 RXP
34	P0RN	10/100 PHY Port #0 RXN
35	P0TP	10/100 PHY Port #0 TXP
36	P0TN	10/100 PHY Port #0 TXN
43	TXD2	10/100 PHY Port #1 TXN, GPIO15, PWM Channel, SPI Slave Clock
44	RXD2	10/100 PHY Port #1 TXP, GPIO14, PWM Channel, SPI Slave Chip Select
40	PWM0	10/100 PHY Port #1 RXN, GPIO17, UART2 Lite TXD, SPI Slave MOSI	4.7K pull down to GND
42	PWM1	10/100 PHY Port #1 RXP, GPIO16, UART2 Lite RXD, SPI Slave MISO
45	P2RP	10/100 PHY Port #2 RXP, GPIO18, PWM Channel
46	P2RN	10/100 PHY Port #2 RXN, GPIO19, PWM Channel
47	P2TP	10/100 PHY Port #2 TXP, GPIO20, PWM Channel
48	P2TN	10/100 PHY Port #2 TXN, GPIO21, PWM Channel
49	SD WP	GPIO22, 10/100 PHY Port #3 TXP, SDXC WP
50	SD CD	GPIO23, 10/100 PHY Port #3 TXN, SDXC CD

Top	Name	Mux	Note
–	GND	Groud
28	SPI CS0	SPI Master Chip Select 0	4.7K pull up to 3.3V
25	SPI CLK	SPI Master Clock	4.7K pull up to 3.3V
26	SPI MISO	SPI Master In Slave Out
27	SPI MOSI	SPI Master Out Slave In	4.7K pull down to GND
24	SPI CS1	SPI Master Chip Select 1	4.7K pull down to GND
21	I2C SD	GPIO5, I2C Data, SDXC D2*	4.7K pull up to 3.3V
20	I2C CLK	GPIO4, I2C Clock, SDXC D3*	4.7K pull up to 3.3V
19	I2S CLK	GPIO3, I2S Bit Clock, SDXC CMD*
18	I2S WS	GPIO2, I2S L/R Clock, SDXC D0*
16	I2S SDI	GPIO0, I2S Data In, SDXC D1*
17	I2S SDO	GPIO1, I2S Data Out	4.7K pull down to GND

Right	Name	Mux	Note
–	GND	Ground
148	RXD1	GPIO12, UART1 Lite RXD
147	TXD1	GPIO13, UART1 Lite TXD	pull up to 3.3V, GPIO/JTAG mode pin
141	GPIO41	GPIO41, JTAG TMS	JTAG needs 10K pull up, R9 -> R6
140	GPIO40	GPIO40, JTAG Clock	JTAG needs 10K pull up, R9 -> R6
139	GPIO39	GPIO39, JTAG Reset	JTAG needs 10K pull up, R9 -> R6
143	GPIO43	GPIO43, JTAG TDO	JTAG needs 10K pull up, R9 -> R6
142	GPIO42	GPIO42, JTAG TDI	JTAG needs 10K pull up, R9 -> R6
138	RST	Reset, touch GND to reset
137	GPIO38	GPIO38
136	GPIO37	GPIO37
–	+3.3VO	+3.3V output	max output current 100mA
–	GND	Ground
–	GND	Ground
–	+1.8VO	+1.8V output	max output current 100mA

Bottom	Name	Mux	Note
–	GND	Ground
51	SD D1	GPIO24, 10/100 PHY Port #3 RXP, SDXC D1
52	SD D0	GPIO25, 10/100 PHY Port #3 RXN, SDXC D0
54	SD CLK	GPIO26, 10/100 PHY Port #4 RXP, SDXC CLK
55	SD CMD	GPIO27, 10/100 PHY Port #4 RXN, SDXC CMD
56	SD D3	GPIO28, 10/100 PHY Port #4 TXP, SDXC D3
57	SD D2	GPIO29, 10/100 PHY Port #4 TXN, SDXC D2
–	+3.3VO	+3.3V output	max output current 100mA
61	USB DP	USB2.0 Data+
62	USB DM	USB2.0 Data-
–	+5.0VI	+5.0V input	min input current 500mA
–	+5.0VI	+5.0V input	min input current 500mA
–	GND	Ground
–	GND	Ground

Middle	Name	Mux	Note
133	PCI CKP	PCI Express External Reference Clock Output+
132	PCI CKN	PCI Express External Reference Clock Output-
130	PCI RXN	PCI Express Differential Receiver RX-
129	PCI RXP	PCI Express Differential Receiver RX+
–	GND	Ground
127	PCI TXP	PCI Express Differential Transmit TX+
126	PCI TXN	PCI Express Differential Transmit TX-
135	PCI RST	PCI Express Device Reset

On VoCore2 Ultimate, ES8388 do not need external clock because we can use VoCore2 system reference clock as its source, in most situation, that will save cost of the BOM.

Set the Pin Function

now, question come, how do we setup every pins function? Sometimes you may want use it as GPIO but sometimes we need to use as clock.

Actually it is same as other MCU(like STM32 and ATMEGA–Arduino) , we have register for every function.

Use this REFCLK pin as example, we can find on MT7628AN datasheet page 117, 2.2 System Control Section, 0x10000060 is that control register.

Its register is 1:0 two bits. (note: on this datasheet, its name is GPIO mode)

We can write 10b to this register, then it will be REFCLK mode.

and after it into REFCLK mode, we can change its frequency, at page 110, 0x1000002c register, bit 11:9 REFCLK0_RATE

And you can use same way to change other pins function 🙂

Also I have a simple tool to do this, please download at vocore.io/v2.html, Directly write to memory/register Section.

mjpeg-streamer is an easy way, but it only able to push mjpeg data, it is a waste because VoCam264 already has h264 stream inside.

So I plan to push h264 data to a RTMP server like nginx-rtmp(-module).

The first way in my mind is to use ffmpeg directly.

Just one command, and it should work: ffmpeg -re -f v4l2 -i /dev/video1 -c:v copy -f flv rtmp://192.168.0.xxx/live

My server is setup at rtmp://192.168.0.xxx/live

Note1: old version ffmpeg do not work well, I am using version 4.2.2. Currently openwrt package has ffmpeg, but it is 3.4.2, we must modify the Makefile and compile again to use latest version. I ave upload Makefile to github.com/vonger/vocore2, in utils folder.

Trying to set codec:h264 pix_fmt:none
parser not found for codec h264, packets or times may be invalid.

Note2: default Makefile will show error about parser, we need to enable h264 parser.

Then ffmpeg is able to push h264 video from camera to server.

Unfortunately, the speed is very slow and video is laggy…Maybe there is something wrong, because it works well on a Linux PC..

I have to find some other way.

My compiled ffmpeg ipk download at here: http://vonger.cn/misc/vocore2/ipk/ffmpeg/

To be continue…