UG-1262
Rev. B | Page 240 of 312
Bits Bit
Name
Settings
Description
Reset
Access
[3:0] MST
Automatic Stretch Mode Control for Master. These bits control automatic stretch
mode for master operation. These bits allow the master to hold the I2C_SCL line low
and gain more time to service an interrupt, load a FIFO, or read a FIFO. Use the
timeout feature to avoid a bus lockup condition where the master indefinitely holds
I2C_SCL low. As a master transmitter, I2C_SCL is automatically stretched from the
negative edge of I2C_SCL (if the master transmit FIFO is empty) before sending an
acknowledge or a no acknowledge for an address byte, or before sending data for a
data byte. Stretching stops when the master transmit FIFO is no longer empty or a
timeout occurs. As a master receiver, the I2C_SCL clock is automatically stretched
from the negative edge of I2C_SCL before sending an acknowledge or a no
acknowledge when the master receive FIFO is full. Stretching stops when the master
receive FIFO is no longer in an overflow condition or a timeout occurs.
0x0 R/W
0000
Automatic master clock stretching disabled.
0001 to
1110
Automatic master clock stretching enabled. The timeout period is defined as follows:
_
(
1)
2
/
ASTRETCH SCL[3:0]
DIV[15 : 8]
DIV[7 : 4]
UCLK CTL1[13 : 8] CTL1[13 : 8]
1111
Automatic master clock stretching enabled with indefinite timeout period.