MOTOROLA
CONFIGURABLE TIMER MODULE 4
MC68336/376
10-18
USER’S MANUAL
D.7.14 PWM Status/Interrupt/Control Register, D.7.15 PWM Period Register,
D.7.16 PWM Pulse Width Register, and D.7.17 PWM Counter Register for informa-
tion concerning PWMSM register and bit descriptions.
10.10 CTM4 Interrupts
The CTM4 is able to generate as many as eleven requests for interrupt service. Each
submodule capable of requesting an interrupt can do so on any of seven levels. Sub-
modules that can request interrupt service have a 3-bit level number and a 1-bit arbi-
tration number that is user-initialized.
The 3-bit level number selects which of seven interrupt signals on the IMB are driven
by that submodule to generate an interrupt request. Of the four priority bits provided
by the IMB to the CTM4 for interrupt arbitration, one of them comes from the chosen
submodule, and the BIUSM provides the other three. Thus, the CTM4 can respond
with two of the 15 possible arbitration numbers.
During the IMB arbitration process, the BIUSM manages the separate arbitration
among the CTM4 submodules to determine which submodule should respond. The
CTM4 has a fixed hardware prioritization scheme for all submodules. When two or
more submodules have an interrupt request pending at the level being arbitrated on
the IMB, the submodule with the lowest number (also the lowest status/interrupt/con-
trol register address) is given the highest priority to respond.
If the CTM4 wins arbitration, it responds with a vector number generated by concate-
nating VECT[7:6] in BIUMCR and the six low-order bits specified by the number of the
submodule requesting service. Table 10-7 shows the allocation of CTM4 submodule
numbers and interrupt vector numbers.
NOTES:
1. Y = M111, where M is the state of the MM bit in SIMCR (Y = $7 or $F).
2. “xx” represents VECT[7:6] in the BIUSM module configuration register.
Table 10-7 CTM4 Interrupt Priority and Vector/Pin Allocation
Submodule
Name
Submodule
Number
Submodule Base
Address
Submodule Binary
Vector Number
BIUSM
0
$YFF4001
None
CPSM
1
$YFF408
None
MCSM2
2
$YFF410
xx0000102
DASM3
3
$YFF418
xx000011
DASM4
4
$YFF420
xx000100
PWSM5
5
$YFF428
xx000101
PWSM6
6
$YFF430
xx000110
PWSM7
7
$YFF438
xx000111
PWSM8
8
$YFF440
xx001000
DASM9
9
$YFF448
xx001001
DASM10
10
$YFF450
xx001010
MCSM11
11
$YFF458
xx001011
FCSM12
12
$YFF460
xx001100
336376UMBook Page 18 Friday, November 15, 1996 2:09 PM