UG-498
ADuCM320 Hardware Reference Manual
Rev. C | Page 116 of 196
Bits
Bit Name
Description
Reset
Access
4
NACKADDR
ACK not received in response to an address. This bit asserts if an ACK is not
received in response to an address. If IENACK is 1, an interrupt is generated
when this bit asserts. This bit is cleared on a read of the I2CMSTA register.
This bit can drive an interrupt.
0x0
RC
3
MRXREQ
Master receive request. This bit asserts when there is data in the receive
FIFO. If IENMRX is 1, an interrupt is generated when this bit asserts. This bit
can drive an interrupt.
0x0
R
2
MTXREQ
Master transmit request. This bit asserts when the direction bit is 0 and the
transmit FIFO is either empty or not full. If IENMTX is 1, an interrupt is
generated when this bit asserts. This bit can drive an interrupt.
0x0
R
[1:0]
MTXFSTA
Master Transmit FIFO status. These 2 bits show the master transmit FIFO
status and can be decoded as follows:
0x0
R
00 = FIFO empty
10 = 1 byte in FIFO
11 = FIFO full
Master Receive Data Register
Address: 0x40003408, Reset: 0x0000, Name: I2C1MRX
Table 159. Bit Descriptions for I2C1MRX
Bits
Bit Name
Description
Reset
Access
[15:8]
RESERVED
Reserved.
0x0
R
[7:0]
ICMRX
Master receive register. This register allows access to the receive data FIFO.
The FIFO can hold 2 bytes.
0x0
R
Master Transmit Data Register
Address: 0x4000340C, Reset: 0x0000, Name: I2C1MTX
Table 160. Bit Descriptions for I2C1MTX
Bits
Bit Name
Description
Reset
Access
[15:8]
RESERVED
Reserved.
0x0
R
[7:0]
I2CMTX
Master transmit register. For test and debug purposes, when read, this
register returns the byte that is currently being transmitted by the master.
That is a byte written to the transmit register can be read back some time
later when that byte is being transmitted on the line.
0x0
RW
This register allows access to the transmit data FIFO. The FIFO can hold 2 bytes.
Master Receive Data Count Register
Address: 0x40003410, Reset: 0x0000, Name: I2C1MRXCNT
Table 161. Bit Descriptions for I2C1MRXCNT
Bits
Bit Name
Description
Reset
Access
[15:9]
RESERVED
Reserved.
0x0
R
8
EXTEND
Extended read. Use this bit if greater than 256 bytes are required on a read.
For example, to receive 412 bytes, write 0x100 (EXTEND = 1) to the
I2CMRXCNT register. Wait for the first byte to be received, then check the
I2CMCRXCNT register for every byte received thereafter. When COUNT
returns to 0, 256 bytes have been received. Then write 0x09C to the
I2CMRXCNT register.
0x0
RW
[7:0]
COUNT
Receive count. Program the number of bytes required minus one to this
register. If just 1 byte is required, write 0 to this register. If greater than 256
bytes are required, use EXTEND.
0x0
RW