S-7750C Datasheet, PDF (14/44 Pages) Seiko Instruments Inc – PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E2PROM CIRCUIT)

PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E²PROM CIRCUIT)
S-7750C
Rev.1.1_00
7. DO7 to DO0 Timer setting
A timer setting register is an 8-bit register, and for each output port (DO7 to DO0), users can set delay time which makes
port output inverted after the timer action starts. Delay time at each output port (DO7 to DO0) is set as seen in Figure 16.
Set “1” in a 1-bit only. This is the data to be set in each timer setting register.
Regarding the timer setting, the following options are selectable.
・ Option to select timer clock (internal oscillation clock / external input clock)
・ Option for delay time (×1 / ×2)
Time reference for timer setting register is defined by these 2 types of option and the timer scale setting register.
(1) When using an internal clock (Typ.)
Option A : (Short-time setting scale, long-time setting scale) = (T, LT) = (5 µs, 320 µs)
Option B : (Short-time setting scale, long-time setting scale) = (T, LT) = (10 µs, 640 µs)
(2) When using an external clock (Period of input clock = T’)
Option A : (Short-time setting scale, long-time setting scale) = (T, LT) = (T’, 64×T’)
Option B : (Short-time setting scale, long-time setting scale) = (T, LT) = (2×T’, 128×T’)
In Figure 16, a timer scale setting register has a short-time setting. In the long-time setting, the port in which the timer
scale setting register is set T changes into LT. For example, if setting the option to the register as seen below, in DO7,
output from the port is inverted after 35 µs (7×5 µs).
Other examples are shown in Figure 17.
・ Option to select timer clock = clock from internal oscillation circuit
・ Option for delay time = ×1
・ Timer scale setting register = 80 h
・ DO7 timer setting register = 40 h
Setting “00h” in the register does not make port output inverted. A timer setting register is the one to be reloaded by
command.
MSB
B7
B6
B5
B4
B3
B2
B1
B0
LSB
DO7
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
DO6
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
DO5
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
DO4
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
DO3
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
DO2
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
DO1
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
DO0
8×T
7×T
6×T
5×T
4×T
3×T
2×T
1×T
R/W
R/W R/W R/W R/W R/W R/W R/W
Figure 16 Timer Setting Register DO7 to DO0 / E²PROM
14
Seiko Instruments Inc.