ACT8865
Rev 7, 22-Mar-16
ERRATA INFO
Disable ACT8865QI303 I2C Interface
Errata Name: ACT8865 creates I2C BUS
To disable the I2C interface of ACT8865QI303 and
configure the SDA and SCL pins to input logic pins,
customer can use I2C to write the following
commands in sequence below:
contention
Device Identification: Parts marked
ACT8865QI405, ACT8865QI305 and
ACT8865QI303
1.Write address 0x0B with 0xE9
2.Write address 0x02 with 0x07
3.Write address 0x03 with 0x01
Description:
The ACT8865 features an I2C interface that only
supports standard single-byte I2C command. After it
detects a START condition, it will wait for its correct
device address to issue the Acknowledge (ACK) by
pulling the SDA low. Therefore, if the ACT8865 I2C
bus shares with a multiple-byte I2C device, it would
accidently issue an ACK once its address is detected
and pull SDA low during mass data transmission
between the MCU and the co-slave device. This
action would cause the I2C BUS to be frozen
unexpectedly.
Disable ACT8865QI305 and ACT8865QI405 I2C
Interface
To disable the I2C interface of ACT8865QI305 and
ACT8865QI405 and configure the SDA and SCL
pins to input logic pins, customer can use I2C to
write the following commands in sequence below:
1.Write address 0x0B with 0xEE
2.Write address 0x02 with 0x07
3.Write address 0x03 with 0x01
4.Write address 0x0B with 0xEF
5.Write address 0x02 with 0x07
6.Write address 0x03 with 0x01
Recommendation:
To avoid the I2C BUS contention, we highly
recommend customer to use ACT8865 I2C
separately from a multiple-byte I2C device such as a
touch screen controller.
However, in case the ACT8865 has to share the
I2C bus with a multiple-byte I2C device, the
ACT8865 features a function to allow customer to
disable its I2C interface to avoid the conflict.
Workaround:
For cases where ACT8865 I2C lines are already
shared with some other components, ACT8865
features a function to allow user to disable its I2C
interface to avoid conflicts. The following I2C write
sequences perform this operation and configure
SDA and SCL as high-Z pin.
: After disable the I2C interface, the ACT8865 will only become accessible by I2C after its power supply is reset.
: Please ensure to ignore any I2C failure report while processing the command sequence.
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