S-7750C Datasheet, PDF (12/44 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
„ Command
1. Reload
This is a 1-byte command. Set bit R / W in “0”. When inputting this command, all registers to be reloaded are once set
in “0”, the data which correspond to the E²PROM is loaded to the register. However, the data in the E²PROM does not
change. The output ports (DO7 to DO0) output “L” once regardless of the data in the control-port register / E²PROM. If
the TIMEN pin is in “H”, the timer starts its action. Besides, port output (DO7 to DO0) is inverted after the time has
elapsed; the time set both by a timer scale setting register and a timer setting register. This is “a timer action”. This is
active from the start to timeout. Regarding the action, refer to “„ Condition to start timer, Port Output and
Register”.
2. Switching access to register / E²PROM
This is a 1-byte command. The mode is in the “register access mode” when R / W = “0”, “E²PROM access mode”
when R / W = “1”. Immediately after power-on, the S-7750C is in the “register access mode”. In this register access
mode, only the register is rewritten, the E²PROM maintains the prior data. But in the “E²PROM access mode”, both
data in the register and in the E²PROM is rewritten. In data Read, access mode data which is being selected by user;
is read.
3. Timer enable register
A timer enable register is an 8-bit register for Write only (it sends back “FFh” during Read). When the TIMEN pin is in
“H”, Write “1” in each bit in the register starts the timer action. The timer action starts at the moment that S-7750C has
received all data of the timer enable command. After writing “1” in the timer enable register, the bit automatically goes
back in “0”. If setting this register in “00h” and the timer setting register in “00h”, a timer does not work. During the
timer action it is impossible to do Write in the timer enable register. A timer enable register is not the one to be
reloaded, because it does not have the corresponding E²PROM.
B7
B6
B5
B4
B3
B2
B1
B0
MSB
TEN 7 TEN 6 TEN 5 TEN 4 TEN 3 TEN 2 TEN 1 TEN 0
LSB
W
W
W
W
W
W
W
W
TEN7 to TEN0 = 0 : DO7 to DO0 Disable to invert output
TEN7 to TEN0 = 1 : DO7 to DO0 Enable to invert output
Figure 11 Timer Enable Register
12
Seiko Instruments Inc.