ATMEGA163 ATMEL [ATMEL Corporation], ATMEGA163 Datasheet - Page 90

• Manufacturer Part Number: ATMEGA163
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Assembly Code Example –
Master Transmitter Mode
90
ATmega163(L)
Figure 52. Formats and States in the Master Transmitter Mode
Successfull
Transmission
to a Slave
Receiver
Next Transfer
Started with a
Repeated Start
Condition
Not Acknowledge
Received After the
Slave Address
Not Acknowledge
Received After a Data
Byte
Arbitration Lost in Slave
Address or Data Byte
Arbitration Lost and
Addressed as Slave
;The Slave being addressed has address 0x64. The code examples also assumes
some sort of error handling routine named ERROR.
;Part specific include file and TWI include file must be included.
; <Initialize registers, including TWAR, TWBR and TWCR>
wait1: in
ldi
out
sbrs r16,TWINT
rjmp wait1
in
cpi
From Master to Slave
From Slave to Master
$08
S
r16, (1<<TWSTA) | (1<<TWEN)
TWCR, r16
r16, TWSR
r16, START
r16,TWCR
SLA
W
; Send START condition
; Wait for TWINT Flag set. This indicates that
; the START condition has been transmitted
; Check value of TWI Status Register.
; If status different from START go to ERROR
MT
A or A
DATA
$18
$20
$38
$68
A
A
A
$78
Other Master
Other Master
n
Continues
Continues
P
$B0
DATA
A
Any Number of Data Bytes
and their Associated Acknowledge Bits
This Number (Contained in TWSR) Corresponds
to a Defined State of the Two-wire Serial Bus
A or A
$28
$30
$38
To Corresponding
States in Slave Mode
A
A
Other Master
Continues
$10
P
S
P
SLA
1142E–AVR–02/03
W
R
MR