
110
EPSON
S1C88409 TECHNICAL MANUAL
CHAPTER 5: PERIPHERAL CIRCUITS AND OPERATION (16-bit Programmable Timer)
5.12.2 Operation mode
The 16-bit programmable timer can be used as two
channels of 8-bit timers or one channel of 16-bit
timer. Two kinds of operation modes are provided
corresponding to this configuration, and it can be
selected by the 8-/16-bit mode selection register
MODE16.
MODE16 register = "0": 8-bit mode
(8 bits
× 2 channels)
MODE16 register = "1": 16-bit mode
(16 bits
× 1 channel)
In the 8-bit mode, Timer 0 and Timer 1 can be
controlled individually.
In the 16-bit mode, the underflow signal of Timer 0
is used as the input clock of Timer 1 so that the
down counters operate as a 16-bit counter.
The timer in the 16-bit mode is controlled with the
control registers for Timer 0 except for the clock
output.
Figure 5.12.2.1 shows the timer configuration
depending on the operation mode and Table
5.12.2.1 shows the configuration of the control
registers.
8-bit data
High-order 8-bit data
[8-bit mode]
8-bit data
Timer 0
input clock
Timer 1
input clock
Interrupt
request
Interrupt
request
[16-bit mode]
Low-order 8-bit data
Timer 0
input clock
Timer 0
underflow
signal
Interrupt
request
Timer 0
Timer 1
Timer 0
Timer 1
Fig. 5.12.2.1 Counter configuration in 8- and 16-bit mode
Table 5.12.2.1(a) Control registers in 8-bit mode
Address
Function
R/W
Init
0
1
Comment
Name
Bit
00FF30
16-bit PTM 8-/16-bit mode selection
–
16-bit PTM0 clock output control
16-bit PTM0 RUN/STOP control
16-bit PTM0 preset
16-bit PTM0 input clock selection
R/W
–
R/W
W
R/W
0
–
0
8-bit
× 2
–
Off
Stop
Invalid
Internal clock
16-bit
–
On
Run
Preset
External clock
"0" when being read
MODE16
–
PTOUT0
PTRUN0
PSET0
CKSEL0
D7
D6
D5
D4
D3
D2
D1
D0
00FF31
–
16-bit PTM1 clock output control
16-bit PTM1 RUN/STOP control
16-bit PTM1 preset
16-bit PTM1 input clock selection
–
R/W
W
R/W
–
0
–
Off
Stop
Invalid
Internal clock
–
On
Run
Preset
External clock
"0" when being read
–
PTOUT1
PTRUN1
PSET1
CKSEL1
D7
D6
D5
D4
D3
D2
D1
D0
Table 5.12.2.1(b) Control registers in 16-bit mode
Address
Function
R/W
Init
0
1
Comment
Name
Bit
00FF30
16-bit PTM 8-/16-bit mode selection
–
Invalid (fixed at "0")
16-bit PTM RUN/STOP control
16-bit PTM preset
16-bit PTM input clock selection
R/W
–
R/W
W
R/W
0
–
0
8-bit
× 2
–
Fixed at "0"
Stop
Invalid
Internal clock
16-bit
–
Invalid
Run
Preset
External clock
"0" when being read
MODE16
–
PTOUT0
PTRUN0
PSET0
CKSEL0
D7
D6
D5
D4
D3
D2
D1
D0
00FF31
–
16-bit PTM clock output control
Invalid (fixed at "0")
–
R/W
W
R/W
–
0
–
Off
Fixed at "0"
–
On
Invalid
"0" when being read
–
PTOUT1
PTRUN1
PSET1
CKSEL1
D7
D6
D5
D4
D3
D2
D1
D0