PIC16LC925T-I/CL View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16LC925T-I/CL

64/68-Pin CMOS Microcontrollers with LCD Driver

Microchip Technology 

PIC16C925/926

Figure 9-11 and Figure 9-12 show master-transmitter

and Master-receiver data transfer sequences.

When a master does not wish to relinquish the bus (by

generating a STOP condition), a Repeated START

condition (Sr) must be generated. This condition is

identical to the START condition (SDA goes high-to-low

while SCL is high), but occurs after a data transfer

Acknowledge pulse (not the bus-free state). This allows

a master to send “commands” to the slave and then

receive the requested information, or to address a dif-

ferent slave device. This sequence is shown in

Figure 9-13.

FIGURE 9-11:

MASTER-TRANSMITTER SEQUENCE

For 7-bit address:

For 10-bit address:

S Slave Address R/W A Data A Data A/A P

'0' (write)

data transferred

(n bytes - Acknowledge)

S Slave Address R/W A1 Slave Address A2

First 7 bits

Second byte

(write)

A master-transmitter addresses a slave-receiver with a

7-bit address. The transfer direction is not changed.

Data A Data A/A P

From master to slave

From slave to master

A = Acknowledge (SDA low)

A = Not Acknowledge (SDA high)

S = START Condition

P = STOP Condition

A master-transmitter addresses a slave-receiver

with a 10-bit address.

FIGURE 9-12:

MASTER-RECEIVER SEQUENCE

For 7-bit address:

For 10-bit address:

S Slave Address R/W A Data A Data A P

'1' (read)

data transferred

(n bytes - Acknowledge)

S Slave Address R/W A1 Slave Address A2

First 7 bits

Second byte

(write)

A master reads a slave immediately after the first byte.

From master to slave

From slave to master

A = Acknowledge (SDA low)

A = Not Acknowledge (SDA high)

S = START Condition

P = STOP Condition

SrSlave Address R/W A3 Data A Data A P

First 7 bits

(read)

A master-transmitter addresses a slave-receiver

with a 10-bit address.

FIGURE 9-13:

COMBINED FORMAT

(read or write)

(n bytes + Acknowledge)

S Slave Address R/W A Data A/A Sr Slave Address R/W A Data A/A P

(read)

Sr = repeated (write)

START Condition

Direction of transfer

may change at this point

Transfer direction of data and Acknowledgment bits depends on R/W bits.

Combined format:

Sr Slave Address R/W A Slave Address A Data A

First 7 bits

Second byte

(write)

Data A/A Sr Slave Address R/W A Data A

First 7 bits

(read)

Data A P

Combined format - A master addresses a slave with a 10-bit address, then transmits

data to this slave and reads data from this slave.

From master to slave

From slave to master

A = Acknowledge (SDA low)

A = Not Acknowledge (SDA high)

S = START Condition

P = STOP Condition

 2001 Microchip Technology Inc.

Preliminary

DS39544A-page 67

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