MC68F375
CONFIGURABLE TIMER MODULE (CTM9)
MOTOROLA
REFERENCE MANUAL
Rev. 25 June 03
13-51
.
13.8.4.1 BIUMCR — BIUSM Module Configuration Register
The BIUMCR register contains nine defined bits that allow the software to control five
functions of the CTM: enabling/disabling of the module, response to FREEZE, vector
base address, interrupt arbitration number and access to the time base buses (via the
time base register).
Table 13-18 BIUSM Register Map
Address
15
8 7
0
0xYF F200
BIUSM module configuration register (BIUMCR)
0xYF F202
BIUSM test register (BIUTST)
0xYF F204
BIUSM time base register (BIUTBR)
BIUMCR — BIUSM Module Configuration Register
0xYF F200
MSB
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LSB
0
STOP
FRZ
0
VECT7
VECT6
IARB2
IARB1
IARB0
0
TBRS1
0
TBRS0
RESET:
0
1
0
Table 13-19 BIUMCR Bit Settings
Bit(s)
Name
Description
15
STOP
Stop enable. The STOP bit, while asserted, activates the FREEZE signal on the SMB regardless
of the state of the FREEZE signal on the IMB. This completely stops the operation of the CTM.
Note that some submodules may validate this signal with internal enable bits. The BIUSM con-
tinues to operate to allow the CPU access to the submodule’s registers. The SMB FREEZE
signal remains active until reset or until the STOP bit is negated by the CPU (via the IMB).
0 = Allows operation of the CTM.
1 = Stops operation of the CTM.
14
FRZ
Freeze enable. The FRZ bit, while asserted, activates the FREEZE signal on the SMB when the
FREEZE signal on the IMB is active. This completely stops the operation of the CTM. Note that
some submodules may validate this signal with internal enable bits. The BIUSM continues to
operate to allow the CPU access to the submodule’s registers. The SMB FREEZE signal
remains active until the FRZ bit is cleared or the IMB FREEZE signal is negated.
0 = Ignores the FREEZE signal on the IMB.
1 = Halts the CTM sub module when the FREEZE signal appears on the IMB.
13
—
Reserved
12:11
VECT[7:8]
Interrupt vector base number. The interrupt vector base number bits select the interrupt vector
base number for the CTM. Of the 8 bits necessary for vector number definition, the six least sig-
nificant bits are programmed by hardware on a submodule basis, while the two remaining bits
are provided by VECT7 and VECT6.
00 = Vector base number 0x00.
01 = Vector base number 0x40.
10 = Vector base number 0x80.
11 = Vector base number 0xC0.
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Freescale Semiconductor, Inc.
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