TMP91CW28 Datasheet, PDF (165/286 Pages) Toshiba Semiconductor – Original CMOS 16-Bit Microcontroller

TMP91CW28
3.10.4 Description of the Registers Used in I²C Bus Mode
This section provides a summary of the registers which control I²C bus operation and
provide I²C bus status information for bus access/monitoring.
SBI0CR1 Bit symbol
(0240H)
Read/Write
Read-modify- Reset value
write
Function
operation is
not
supported.
Serial Bus Interface Control Register 1
7
6
5
4
3
2
1
0
BC2
BC1
BC0
ACK
SCK2
SCK1
SCK0/
SWRMON
W
R/W
W
R/W
0
0
0
0
0
0
0/1 (Note 3)
Number of bits per transfer (Note 1)
ACK clock
pulse
0: No ACK
1: ACK
Internal SCL output clock frequency
(Note 2)/Software reset monitor
On writes: SCK[2:0] = Internal SCL output clock frequency
000 n = 5 − (Note4)
001 n = 6 − (Note4) Assumptions:
010 n = 7 73.5 kHz System clock: fc
011 n = 8 37.9 kHz Clock gear: fc/1
100 n = 9 19.2 kHz
101 n = 10 9.7 kHz
110 n = 11 4.9 kHz
fc = 10 MHz (Output to the SCL pin)
Frequency = ^fc [Hz]
2ⁿ + 8
111 (Reserved) (Reserved)
On reads: SWRMON = Software reset monitor
0 Software reset operation is in progress.
1 Initial Data
Acknowledgement clock generation
0 No acknowledgement clock pulse is generated.
1 An acknowledgement clock pulse is generated.
Number of bits per transfer
ACK = 0
BC[2:0] _{Number of Data}
clock cycles length
000
8
8
001
1
1
010
2
2
011
3
3
100
4
4
101
5
5
110
6
6
111
7
7
ACK = 1
Number of Data
clock cycles length
9
8
2
1
3
2
4
3
5
4
6
5
7
6
8
7
Note 1: Clear the BC[2:0] field to 000 before switching the operating mode to “Clock-synchronous” 8-bit SIO mode.
Note 2: For details on the SCL bus clock frequency, refer to section 3.10.5 (3) “Serial clock”.
Note 3: Initial data of SCK0 is 0, SWRMON is 1.
Note 4: This I²C bus circuit dose not support fast mode, it supports standard mode only. Although the I²C bus circuit
itself allows the setting of a baud rate over 100 kbps, the compliance with the I²C specification is not
guaranteed in that case.
Figure 3.10.4 I²C Bus Mode Registers (1) (SBI0CR1 for the SBI0)
91CW28-163
2006-03-24