21 i
2
C SlaVe (i2CS)
S1C17624/604/622/602/621 TeChniCal Manual
Seiko epson Corporation
21-1
I
21
2
C Slave (I2CS)
i2CS Module Overview
21.1
The S1C17624/604/622/602/621 includes an I
2
C slave (I2CS) module that supports two-wire communications. The
I2CS module operates as an I
2
C bus slave device and can communicate with an I
2
C-compliant master device.
The following shows the main features of I2CS:
• Operates as an I
2
C bus slave device.
• Supports standard (100 kbps) and fast (400 kbps) modes.
• Supports 8-bit data length only (MSB first).
• Supports 7-bit addressing mode.
• Includes one-byte receive data buffer and one-byte transmit data buffer.
• Can detect start and stop conditions.
• Supports half-duplex communications.
• Supports clock stretch function.
• Supports forced bus release function.
• Includes a noise filter function to help improve the reliability of data transfers.
• Can generate transmit buffer empty, receive buffer full, and bus status interrupts.
Figure 21.1.1 shows the I2CS configuration.
SCL1
#BFR
Shift register
SDA1
SDA
SCL
Internal bus
ITC
I
2
C Slave
Bus I/F
and
control
registers
Shift register
Clock/transfer control
Noise
filter
Interrupt
control
1.1 I2CS Module Configuration
Figure 21.
note: The I2CS module does not support general call address and 10-bit address mode.
i2CS input/Output Pins
21.2
Table 21.2.1 lists the I2CS pins.
2.1 List of I2CS Pins
Table 21.
Pin name
I/O
Qty
Function
SDA1
I/O
1
I2CS data input/output pin (see Note below)
Inputs serial data from the I
2
C bus. Also outputs serial data to the I
2
C bus.
SCL1
I/O
1
I2CS clock input/output pin (see Note below)
Inputs SCL line status from the I
2
C bus. Also outputs a low level to put the I
2
C bus
into clock stretch status.
#BFR
I
1
I
2
C bus free request input pin
A Low pulse input to this pin requests the I2CS to release the I
2
C bus. When the
bus free request input has been enabled with software, a Low pulse initializes the
communication process of the I2CS module and sets the SDA1 and SCL1 pins
into high impedance.