ATTINY88-15MZ Atmel, ATTINY88-15MZ Datasheet - Page 157

• Manufacturer Part Number: ATTINY88-15MZ
• Description: IC MCU AVR 8B 8KB FLASH 32QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY88-15MZ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 28
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

15.9.4
9157B–AVR–01/10
TWDR – TWI Data Register
• Bits 1..0 – TWPS: TWI Prescaler Bits
These bits can be read and written, and control the bit rate prescaler.
Table 15-7.
To calculate bit rates, see
used in the equation.
In Transmit mode, TWDR contains the next byte to be transmitted. In Receive mode, the TWDR
contains the last byte received. It is writable while the TWI is not in the process of shifting a byte.
This occurs when the TWI Interrupt Flag (TWINT) is set by hardware. Note that the Data Regis-
ter cannot be initialized by the user before the first interrupt occurs. The data in TWDR remains
stable as long as TWINT is set. While data is shifted out, data on the bus is simultaneously
shifted in. TWDR always contains the last byte present on the bus, except after a wake up from
a sleep mode by the TWI interrupt. In this case, the contents of TWDR is undefined. In the case
of a lost bus arbitration, no data is lost in the transition from Master to Slave. Handling of the
ACK bit is controlled automatically by the TWI logic, the CPU cannot access the ACK bit directly.
• Bits 7..0 – TWD: TWI Data Register
These eight bits constitute the next data byte to be transmitted, or the latest data byte received
on the 2-wire Serial Bus.
Bit
Read/Write
Initial Value
TWPS1
0
0
1
1
TWI Bit Rate Prescaler
TWD7
R/W
7
1
TWD6
R/W
TWPS0
0
1
0
1
6
1
“Bit Rate Generator Unit” on page
TWD5
R/W
5
1
TWD4
R/W
4
1
Prescaler Value
1
4
16
64
TWD3
R/W
3
1
ATtiny88 Automotive
TWD2
R/W
2
1
134. The value of TWPS1..0 is
TWD1
R/W
1
1
TWD0
R/W
0
1
TWDR
157