ACT8946AQJ203-T
Rev 1.0, 08-Jul-16
ERRATA INFO
Errata Name: ACT8946A creates I2C BUS
contention
Device Identification: Parts marked
ACT8946AQJ203
Description:
The ACT8946A 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 ACT8946A 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.
Recommendation:
To avoid the I2C BUS contention, we highly
recommend customer to use ACT8946A I2C
separately from a multiple-byte I2C device such as a
touch screen controller.
However, in case the ACT8946A has to share the
I2C bus with a multiple-byte I2C device, the
ACT8946A features a function to allow customer to
disable its I2C interface to avoid the conflict.
Workaround:
For cases where ACT8946A I2C lines are already
shared with some other components, ACT8946A
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.
Disable ACT8946AQJ203 I2C Interface
To disable the I2C interface of ACT8946AQJ203
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 0xE8
2.Write address 0x02 with 0x07
3.Write address 0x03 with 0x01
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