MC68HC12 Datasheet, PDF (312/478 Pages) Motorola, Inc – The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit

Inter IC Bus
Table 17-2. IIC Divider and SDA Hold values
IBC5-0
(hex)
1B
1C
1D
1E
1F
SCL Divider SDA Hold
(clocks)
(clocks)
128
17
144
25
160
25
192
33
240
33
IBC5-0
(hex)
3B
3C
3D
3E
3F
SCL Divider
(clocks)
2048
2304
2560
3072
3840
SDA Hold
(clocks)
257
385
385
513
513
IBCR — IIC Bus Control Register
Bit 7
6
IBEN
IBIE
RESET:
0
0
5
MS/SL
0
4
Tx/Rx
0
3
TXAK
0
2
RSTA
0
$00E2
1
Bit 0
0
IBSWAI
0
0
Read and write anytime
IBEN — IIC Bus Enable
This bit controls the software reset of the entire IIC module.
0 = The module is reset and disabled. This is the power-on reset
situation. When low the IIC system is held in reset but registers
can still be accessed.
1 = The IIC system is enabled. This bit must be set before any other
IBCR bits have any effect.
If the IIC module is enabled in the middle of a byte transfer the
interface behaves as follows: slave mode ignores the current transfer
on the bus and starts operating whenever a subsequent start
condition is detected. Master mode will not be aware that the bus is
busy, hence if a start cycle is initiated then the current bus cycle may
become corrupt. This would ultimately result in either the current bus
master or the IIC module losing arbitration, after which bus operation
would return to normal.
NOTE: To prevent glitches from appearing on the SDA & SCL lines during reset
of the IIC module, set PORTIB bit 6 & 7 to 1 before clearing the IBEN bit.
Technical Data
312
Inter IC Bus
MC68HC912DT128A — Rev 4.0
MOTOROLA