TMP91C820A Datasheet, PDF (110/360 Pages) Toshiba Semiconductor – Original CMOS 16-Bit Microcontroller

TMP91C820A
3.7 8-Bit Timers (TMRA)
The TMP91C820A features 4 built-in 8-bit timers.
These timers are paired into four modules: TMRA01 and TMRA23. Each module consists of
two channels and can operate in any of the following four operating modes.
• 8-bit interval timer mode
• 16-bit interval timer mode
• 8-bit programmable square wave pulse generation output mode (PPG: Variable duty
cycle with variable period)
• 8-bit pulse width modulation output mode (PWM: Variable duty cycle with constant
period)
Figure 3.7.1 and 3.7.2 show block diagrams for TMRA01 and TMRA23.
Each channel consists of an 8-bit up counter, an 8-bit comparator and an 8-bit timer register.
In addition, a timer flip-flop and a prescaler are provided for each pair of channels.
The operation mode and timer flip-flops are controlled by five controls SFRs (Special function
registers).
Each of the two modules (TMRA01 and TMRA23) can be operated independently. All modules
operate in the same manner; hence only the operation of TMRA01 is explained here.
The contents of this chapter are as follows.
3.7.1 Block Diagrams
3.7.2 Operation of Each Circuit
3.7.3 SFRs
3.7.4 Operation in Each Mode
(1) 8-bit timer mode
(2) 16-bit timer mode
(3) 8-bit PPG (Programmable pulse generation) output mode
(4) 8-bit PWM (Pulse width modulation) output mode
(5) Settings for each mode
(6) LCDC and MELODY/ALARM circuit supply mode
Table 3.7.1 Registers and Pins for Each Module
Module
TMRA01
TMRA23
External
pin
Input pin for external
clock
Output pin for timer
flip-flop
Timer run register
SFR
(Address)
Timer register
Timer mode register
Timer flip-flop control
register
TA0IN
(Shared with PB0)
TA1OUT
(Shared with PB1)
TA01RUN (0100H)
TA0REG (0102H)
TA1REG (0103H)
TA01MOD (0104H)
No
TA3OUT
(Shared with PB5)
TA23RUN (0108H)
TA2REG (010AH)
TA3REG (010BH)
TA23MOD (010CH)
TA1FFCR (0105H) TA3FFCR (010DH)
91C820A-108
2006-01-31