MPC555
/
MPC556
MODULAR INPUT/OUTPUT SUBSYSTEM (MIOS1)
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
15-13
15.9.1.1 MCPSM Status/Control Register (MCPSMCSCR)
This register contains status and control information for the MCPSM.
15.10 MIOS Modulus Counter Submodule (MMCSM)
The MMCSM is a versatile counter submodule capable of performing complex count-
ing and timing functions, including modulus counting, in a wide range of applications.
The MMCSM may also be configured as an event counter, allowing the overflow flag
to be set after a predefined number of events (internal clocks or external events), or
Table 15-9 MCPSM Address Map
Address
Register
0x30 6810 –
0x30 6814
Reserved
0x30 6816
MCPSM Status/Control Register (MCPSMSCR)
See
MCPSMSCR
— MCPSM Status/Control Register
0x30 6816
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
PREN FREN
RESERVED
PSL
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 15-10 MCPSMSCR Bit Descriptions
Bit(s)
Name
Description
0
PREN
Prescaler enable. This active high read/write control bit enables the MCPSM counter. The PREN
bit is cleared by reset.
0 = MCPSM counter disabled.
1 = MCPSM counter enabled.
1
FREN
Freeze enable. This active high read/write control bit when set make possible a freeze of the
MCPSM counter if the MIOB freeze line is activated. Note that this line is active when the
MIOS1MCR STOP bit is set or when the MIOS1MCR FREN bit and the IMB3 FREEZE line are
set.
When the MCPSM is frozen, it stops counting. Then when the FREN bit is reset or when the
freeze condition on the MIOB is negated, the counter restarts from where it was before being
frozen. The FREN bit is cleared by reset.
0 = MCPSM counter not frozen.
1 = Selectively stops MIOS1 operation when the FREEZE signal appears on the IMB3.
2:11
—
Reserved
12:15
PSL
Clock prescaler. This 4-bit read/write data register stores the modulus value for loading into the
clock prescaler. The new value is loaded into the counter on the next time the counter equals
one or when disabled (PREN bit = 0). Divide ratios are as follows:
0000 = 16
0001 = No counter clock output
0010 = 2
0011 = 3
.
.
.
1110 = 14
1111 = 15
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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