ATAVRSB202 Atmel, ATAVRSB202 Datasheet - Page 172

• Manufacturer Part Number: ATAVRSB202
• Description: KIT BATT MGMT FOR ATMEGA32HVB
• Manufacturer: Atmel

Specifications of ATAVRSB202

• Main Purpose: *
• Embedded: *
• Utilized Ic / Part: *
• Primary Attributes: *
• Secondary Attributes: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

27.7.2
8042B–AVR–06/10
Master Receiver Mode
In the Master Receiver mode, a number of data bytes are received from a slave transmitter (see
Figure
mat of the following address packet determines whether Master Transmitter or Master Receiver
mode is to be entered. If SLA+W is transmitted, MT mode is entered, if SLA+R is transmitted,
MR mode is entered. All the status codes mentioned in this section assume that the prescaler
bits are zero or are masked to zero.
Figure 27-13. Data Transfer in Master Receiver Mode
A START condition is sent by writing the following value to TWCR:
TWEN must be written to one to enable the Two-wire Serial Interface, TWSTA must be written to
one to transmit a START condition and TWINT must be set to clear the TWINT flag. The TWI will
then test the Two-wire Serial Bus and generate a START condition as soon as the bus becomes
free. After a START condition has been transmitted, the TWINT flag is set by hardware, and the
status code in TWSR will be 0x08 (see
SLA+R must be transmitted. This is done by writing SLA+R to TWDR. Thereafter the TWINT bit
should be cleared (by writing it to one) to continue the transfer. This is accomplished by writing
the following value to TWCR:
When SLA+R have been transmitted and an acknowledgment bit has been received, TWINT is
set again and a number of status codes in TWSR are possible. Possible status codes in Master
mode are 0x38, 0x40, or 0x48. The appropriate action to be taken for each of these status codes
is detailed in
when the TWINT flag is set high by hardware. This scheme is repeated until the last byte has
been received. After the last byte has been received, the MR should inform the ST by sending a
NACK after the last received data byte. The transfer is ended by generating a STOP condition or
a repeated START condition. A STOP condition is generated by writing the following value to
TWCR:
TWCR
Value
TWCR
Value
SDA
SCL
27-13). In order to enter a Master mode, a START condition must be transmitted. The for-
Device 1
RECEIVER
MASTER
Table 27-12 on page
TWINT
TWINT
1
1
TRANSMITTER
TWEA
TWEA
Device 2
SLAVE
X
X
TWSTA
TWSTA
171. Received data can be read from the TWDR Register
1
0
Device 3
Table 27-2 on page
TWSTO
TWSTO
0
0
........
ATmega16HVB/32HVB
TWWC
TWWC
X
X
Device n
170). In order to enter MR mode,
V
BUS
TWEN
TWEN
1
1
R1
–
0
–
0
R2
TWIE
TWIE
X
X
172