Registers

NAME ADDRESS WIDTH
REG_I2CDATA 0x04004500 1
REG_I2CCNT 0x04004501 1

REG_I2CDATA

BIT DESCRIPTION
0 R/W, clear for write, set for read
1 Start/device select bit?
2 Restart/device reselect bit?
3 ?
4 SCL hold. When clear SCL is being held low, set when SCL is high. This bit must always be set(by reading CNT again) after writing REG_I2CCNT. This bit must be set when writing blocks of data(more than 1 byte) with bit0 clear.
5 SCL, toggle this for each loop iteration(in the loop execute the I2C WR code) with max 8 iterations where the loop exits successfully when bit 4 is set. This bit must be set when writing blocks of data(more than 1 byte) with bit0 clear.
6 Unknown, always set when writing to CNT?
7 Enable/busy

Protocol

Wait for the busy bit to clear. Write the device address to REG_I2CDATA, then write 0xc2(busy/enable, bit 6, and start bit 1 set) to REG_I2CCNT. Execute swiWaitByLoop for a device-specific duration, then write the register address to REG_I2CDATA, and write 0xc0 to REG_I2CCNT.(busy/enable and bit 6 set) Wait with swiWaitByLoop device duration, then write the data to REG_I2CDATA when writing. When reading, write the device address to REG_I2CDATA and write 0xc2 to REG_I2CCNT. When the delay value is zero, write 0xc1 | i<<5 to REG_I2CCNT, otherwise write 0xc0 | i<<5 to REG_I2CCNT, wait for busy to clear, delay, then write 0xc5 to REG_I2CCNT. For writing i is the loop i for iteration, for reading replace that with 1. When reading, read the data from REG_I2CCNT. Return a error if REG_I2CCNT bit 4 SCL hold is set, otherwise return normal.

I2C devices

I2C device table:

Device index in table Device address Device swiWaitByLoop delay Device description
0 0x00 0x00 Camera0?
1 0x80 0x00 Camera1?
2 0x00 0x00 ?
3 0x00 0x00 ?
4 0x7A 0x180 Power management
5 0x78 0x00 ?
6 0xA0 0x00 ?

Power management

When registers 0x70 and 0x11 are set to 1 in that order, a power cycle is done.

REGISTER WIDTH DESCRIPTION
0x11 1 System reset register 2.
0x12 1 Might be MMC bus power related, unknown.
0x31 1 Cameras' power? Value 0 turns off power to cameras? Values 1/2 activates a camera's power?
0x70 1 System reset register 1.