UG-1262
Rev. B | Page 237 of 312
Bits
Bit
Name Settings Description
Reset Access
2 STXREQ
Slave Transmit Request. If SCTL, Bit 5 = 0, this bit is set when the direction bit for a
transfer is received high. As long as the transmit FIFO is not full, this bit remains
asserted. Initially, this bit is asserted on the negative edge of the SCL pulse that
clocks in the direction bit (if the device address matches). If SCTL, Bit 5 = 1, this bit is
set when the direction bit for a transfer is received high. As long as the transmit FIFO
is not full, this bit remains asserted. Initially, this bit is asserted after the positive edge
of the I2C_SCL pulse that clocks in the direction bit (if the device address matches).
This bit is cleared on a read of the SSTAT register.
0x0 RC
1 STXUR
Slave Transmit FIFO Underflow. This bit is set if a master requests data from the
device, and the transmit FIFO is empty for the rising edge of SCL.
0x0 RC
0 STXFSEREQ
Slave Transmit FIFO Status or Early Request. If SCTL, Bit 5 = 0, this bit is asserted
whenever the slave transmit FIFO is empty. If SCTL, Bit 5 = 1, this bit is set when the
direction bit for a transfer is received high. This bit asserts on the positive edge of the
I2C_SCL clock pulse that clocks in the direction bit if the device address matches. This
bit only asserts once for a transfer and is cleared when read if SCTL, Bit 5 is asserted.
0x1 R/W
SLAVE RECEIVE REGISTER
Address: 0x40003030, Reset: 0x0000, Name: SRX
Table 294. Bit Descriptions for SRX
Bits Bit
Name Settings Description
Reset
Access
[15:8] Reserved
Reserved.
0x0 R
[7:0]
SRX
Slave Receive Register.
0x0
R
SLAVE TRANSMIT REGISTER
Address: 0x40003034, Reset: 0x0000, Name: STX
Table 295. Bit Descriptions for STX
Bits Bit
Name Settings Description
Reset
Access
[15:8] Reserved
Reserved.
0x0 R
[7:0]
ISTX
Slave Transmit Register.
0x0
R/W
HARDWARE GENERAL CALL ID REGISTER
Address: 0x40003038, Reset: 0x0000, Name: ALT
Table 296. Bit Descriptions for ALT
Bits Bit
Name Settings
Description
Reset Access
[15:8] Reserved
Reserved.
0x0 R
[7:0] ALT
Slave Alternative. This register is used in conjunction with SCTL, Bit 3 to match a master
generating a hardware general call. This register is used when a master device cannot
be programmed with the address of a slave, and instead the slave must recognize the
address of the master.
0x0 R/W
FIRST SLAVE ADDRESS DEVICE ID REGISTER
Address: 0x4000303C, Reset: 0x0000, Name: ID0
Table 297. Bit Descriptions for ID0
Bits Bit
Name Settings
Description
Reset Access
[15:8] Reserved
Reserved.
0x0 R
[7:0] ID0
Slave Device ID 0. ID0, Bits[7:1] are programmed with the device ID. ID0, Bit 0 is don't care.
See SCTL, Bit 1 to see how this register is programmed with a 10-bit address. Take care to
avoid I
2
C reserved slave addresses with values less than 0x10 and greater than 0xF6.
0x0 R/W