mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 293

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

13.4.2 GPT Interrupts
MC68HC16Y3/916Y3
USER’S MANUAL
For each bit in TFLG1 and TFLG2 there is a corresponding bit in TMSK1 and TMSK2
in the same bit position. If a mask bit is set and an associated event occurs, a hardware
interrupt request is generated.
In order to re-enable a status flag after an event occurs, the status flags must be
cleared. Status registers are cleared in a particular sequence. The register must first
be read for set flags, then zeros must be written to the flags that are to be cleared. If
a new event occurs between the time that the register is read and the time that it is
written, the associated flag is not cleared.
The GPT has 11 internal sources that can cause it to request interrupt service (refer
to Table 13-2). Setting bits in TMSK1 and TMSK2 enables specific interrupt sources.
TMSK1 and TMSK2 are 8-bit registers that can be addressed individually or as one
16-bit register. The registers are initialized to zero at reset. For each bit in TMSK1 and
TMSK2 there is a corresponding bit in TFLG1 and TFLG2 in the same bit position.
TMSK2 also controls the operation of the timer prescaler. Refer to 13.7 Prescaler for
more information.
The value of the interrupt priority level (IPL[2:0]) field in the interrupt control register
(ICR) determines the priority of GPT interrupt requests. IPL[2:0] values correspond to
MCU interrupt request signals IRQ[7:1]. IRQ7 is the highest priority interrupt request
signal; IRQ1 is the lowest-priority signal. A value of %111 causes IRQ7 to be asserted
when a GPT interrupt request is made; lower field values cause corresponding lower-
priority interrupt request signals to be asserted. Setting field value to %000 disables
interrupts.
Mnemonic
PAOVF
I4/O5F
OC1F
OC2F
OC3F
OC4F
IC1F
IC2F
IC3F
PAIF
Flag
TOF
Freescale Semiconductor, Inc.
For More Information On This Product,
Table 13-1 GPT Status Flags
GENERAL-PURPOSE TIMER
Go to: www.freescale.com
Assignment
Register
TFLG1
TFLG1
TFLG1
TFLG1
TFLG1
TFLG1
TFLG1
TFLG1
TFLG2
TFLG2
TFLG2
Input capture 4/output compare 5
Pulse accumulator overflow
Pulse accumulator input
Output compare 1
Output compare 2
Output compare 3
Output compare 4
Input capture 1
Input capture 2
Input capture 3
Timer overflow
Source
MOTOROLA
13-5