ADuCM320 Hardware Reference Manual
UG-498
Rev. C | Page 111 of 196
Bits
Bit Name
Description
Reset
Access
2
STXREQ
Slave transmit request. If EARLYTXR = 0, STXREQ is set when the direction
bit for a transfer is received high. Thereafter, as long as the transmit FIFO is
not full, this bit remains asserted. Initially, it is asserted on the negative
edge of the SCL pulse that clocks in the direction bit (if the device address
matched also).
0x0
RC
If EARLYTXR = 1, STXREQ is set when the direction bit for a transfer is
received high. Thereafter, as long as the transmit FIFO is not full this bit
remains asserted. Initially, it is asserted after the positive edge of the SCL
pulse that clocks in the direction bit (if the device address matched also).
This bit is cleared on a read of the I2C0SSTA register.
1
STXUR
Slave transmit FIFO underflow. Is set if a master requests data from the
device, and the Tx FIFO is empty for the rising edge of SCL.
0x0
RC
0
STXFSEREQ
Slave Tx FIFO status or early request. If EARLYTXR = 0, this bit is asserted
whenever the slave Tx FIFO is empty.
0x1
RW
If EARLYTXR = 1, TXFSEREQ is set when the direction bit for a transfer is
received high. It asserts on the positive edge of the SCL clock pulse that
clocks in the direction bit (if the device address matched also). It only
asserts once for a transfer. It is cleared when read if EARLYTXR is asserted.
Slave Receive Register
Address: 0x40003030, Reset: 0x0000, Name: I2C0SRX
Table 147. Bit Descriptions for I2C0SRX
Bits
Bit Name
Description
Reset
Access
[15:8]
RESERVED
Reserved
0x0
R
[7:0]
I2C0SRX
Slave receive register
0x0
R
Slave Transmit Register
Address: 0x40003034, Reset: 0x0000, Name: I2C0STX
Table 148. Bit Descriptions for I2C0STX
Bits
Bit Name
Description
Reset
Access
[15:8]
RESERVED
Reserved
0x0
R
[7:0]
I2C0STX
Slave transmit register
0x0
RW
Hardware General Call ID Register
Address: 0x40003038, Reset: 0x0000, Name: I2C0ALT
Table 149. Bit Descriptions for I2C0ALT
Bits
Bit Name
Description
Reset
Access
[15:8]
RESERVED
Reserved.
0x0
R
[7:0]
ALT
Slave Alt. This register is used in conjunction with I2C0SCON[3] to match a
master generating a hardware general call. It is used in the case where a
master device cannot be programmed with a slave's address and instead
the slave must recognize the master's address.
0x0
RW