iSC5 Camera PCB wiring

• Sensor Board and GPIO_MS1[6]
• Powering the Speaker
• Powering the WiFi Module

In the stock firmware there is the following code in the '/etc/init.d/rcS' file:

#power on sensor
/bin/gpio_ms1 -n 6 -m 1 -v 1

'gpio_ms1' binary when compiled with '-DSN9866X' flag maps gpio_ms1[7]…gpio_ms1[3] on aud[4]…aud[0]. In other words for each call with '-n X' flag where X is a number from 3 to 7 it internally calls 'gpio_aud' binary with argument 'Y' where Y is X minus 3. So that the line above means that aud[3] is set to high.

aud[3] line of the SOC is going to pin24 on the camera board connector. The line from the pin goes to the seat for a resistor which is left unsoldered. There are may be other vias under the socket however but the fact that even without setting aud[3] high the sensor works well.

The speaker is driven by the SGM4895 power amp. The shutdown controlling line “nSHDN” of the speaker is connected to aud[4] line of the SoC. So that you need to set aud[4] gpio to high in order to play sound.

The 3V3 bus of the wifi module is sourced from the p-channel MOSFET WP3401 (sot23, mark WP1J). The gate of the transistor is pulled down by a resistor and connected to the line gpio[6] of the SoC. If you need to hard-reset the wifi module then you should kill all networking software, unload the driver and set gpio[6] to high for a few seconds.