S7760A Datasheet, PDF (4/54 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-7760A
Rev.2.0_01
 General Description of Pin Function
1. SDA (Serial data I/O) pin
The SDA pin transmits serial data bi-directionally, is comprised of a signal input pin and a pin with Nch transistor open
drain output. In use, generally, connect the SDA line to any other device which has the open-drain or open-collector
output with Wired-OR connection by pulling up to VCCH by a resistor.
2. SCL (Input for serial clock) pin
The SCL pin is an input pin for serial clock, processes a signal at a rising/falling edge of SCL clock. Pay attention fully
to the rising/falling time and comply with specifications.
3. WP (Input for Write protect) pin
This pin performs Write Protect to E²PROM (This pin does not have a function for Write protect to the register).
Set the WP pin in VCCH when using the Write Protect function. If not, set the WP pin to GND.
4. TIMEN (Input for timer enable)/RESX (Input for reset bar) pin
Select TIMEN or RESX by option.
The TIMEN pin controls enable (“H”)/disable (“L”)/Start (“L”→”H”) in the timer action (inversion of digital output due to
elapsed period). Refer to the description of related register in “ Command” and “ Condition to Start Timer”
regarding details of timer action.
The RESX pin has the negative logic, is a pin to reset. This pin initializes the circuit with “L” input, and performs its
regular action (the status of reset release) by inputting “H”. This pin goes in its reload action immediately after
releasing reset, thus by initializing, the value of related register is reloaded to the data that E²PROM has. If a user
selects the RESX pin, the TIMEN pin’s function will be invalid so that the internal signal of TIMEN is fixed in “L”.
5. CLK (Clock input)/BPDX (Input for bus pull-down bar) pin
As for primary clock for circuits, users can select either from the internal oscillation circuit or input it externally by
option. In case of using an external clock input, this pin works as the CLK pin to input clock by itself. In case of using
an internal oscillation circuit, users can set this pin as the BPDX pin by option. With “L” input from the BPDX pin, SDA
and SCL in I²C-bus interface are forcibly pulled-down. This pin performs its regular action by inputting “H”. Users also
can select the setting which does not have an internal oscillation circuit or bus pull-down for this pin.
6. DO0, DO1, DO2, DO3 (Digital output) pin
These are lower 4 channels in the digital output ports. Their default values are equal to the ones of a control port
register during output. These lower 4 channels are for timer action. Its output inverts after; the timer starts and delay
time has elapsed.
7. DO4, DO5, DO6, DO7 (Digital output) pin
These are the higher 4 channels in the digital output ports. Their default values are equal to the ones of a control port
register during output. These higher 4 channels have fixed output. The elapsed period does not make outputs
inverted.
8. VSS pin
Connect to GND.
9. VCCH pin
Except for the output ports, the power supply is applied to the entire circuit via this pin. Regarding the voltage’s value
to be applied to this pin, refer to “ Recommended Operating Conditions”.
10. VCCL pin
This pin is to apply the power supply for the output ports. Regarding the voltage’s value to be applied to this pin, refer
to “ Recommended Operating Conditions”.
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