MC68HC705BD3 FREESCALE [Freescale Semiconductor, Inc], MC68HC705BD3 Datasheet - Page 54

• Manufacturer Part Number: MC68HC705BD3
• Description: High-density complementary metal oxide semiconductor (HCMOS) microcontroller unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

7
7.3.4
The MIF and MAL bits are software clearable; while the other bits are read only.
MCF - Data Transfer Complete
When MCF is set, the MIF (M-Bus interrupt) bit is also set. An M-Bus interrupt is generated if the
MIEN bit is set.
MAAS - Addressed as Slave
This MAAS bit is set when its own specific address (M-Bus Address register) matches the calling
address. When MAAS is set, the MIF (M-Bus interrupt) bit is also set. An interrupt is generated if
the MIEN bit is set. Then CPU needs to check the SRW bit and set its MTX bit accordingly. Writing
to the M-Bus Control register clears this bit.
MBB - Bus Busy
This bit indicates the status of the bus. When a START signal is detected, MBB is set. When a
STOP signal is detected, it is cleared.
MAL - Arbitration Lost
This arbitration lost flag is set when the M-Bus master loses arbitration during a master
transmission mode. When MAL is set, the MIF (M-Bus interrupt) bit is also set. This bit must be
cleared by software.
7-8
1 (set)
0 (clear) –
1 (set)
0 (clear) –
1 (set)
0 (clear) –
1 (set)
0 (clear) –
Address
$001A
M-Bus Status Register (MSR)
MCF
–
–
–
–
bit 7
A byte transfer has been completed.
A byte is being transfer.
Currently addressed as a slave.
Not currently addressed.
M-Bus busy.
M-Bus idle.
Lost arbitration in master mode.
No arbitration lost.
MAAS
bit 6
MBB
bit 5
M-BUS SERIAL INTERFACE
bit 4
MAL
bit 3
SRW
bit 2
bit 1
MIF
RXAK
bit 0
1000 0001
on reset
MC68HC05BD3
State
TPG