ATTINY88-MU Atmel, ATTINY88-MU Datasheet - Page 124

• Manufacturer Part Number: ATTINY88-MU
• Description: MCU AVR 8K ISP FLASH 1.8V 32-QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY88-MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 12MHz
• 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): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Processor Series: ATTINY8x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: 2-Wire, I2S, SPI
• Maximum Clock Frequency: 12 MHz
• Number Of Programmable I/os: 28
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATQT600, ATAVRTS2080B
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Package: 32QFN EP
• Device Core: AVR
• Family Name: ATtiny
• Maximum Speed: 12 MHz
• Operating Supply Voltage: 2.5|3.3|5 V
• Cpu Family: ATtiny
• Device Core Size: 8b
• Frequency (max): 12MHz
• Total Internal Ram Size: 512Byte
• # I/os (max): 28
• Number Of Timers - General Purpose: 2
• Operating Supply Voltage (typ): 2.5/3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 1.8V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 32
• Package Type: QFN EP
• For Use With: ATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIPATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVR
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14.3
14.3.1
14.3.2
124
SS Pin Functionality
ATtiny48/88
Slave Mode
Master Mode
When the SPI is configured as a Slave, the Slave Select (SS) pin is always input. When SS is
held low, the SPI is activated, and MISO becomes an output if configured so by the user. All
other pins are inputs. When SS is driven high, all pins are inputs, and the SPI is passive, which
means that it will not receive incoming data. Note that the SPI logic will be reset once the SS pin
is driven high.
The SS pin is useful for packet/byte synchronization to keep the slave bit counter synchronous
with the master clock generator. When the SS pin is driven high, the SPI slave will immediately
reset the send and receive logic, and drop any partially received data in the Shift Register.
When the SPI is configured as a Master (MSTR in SPCR is set), the user can determine the
direction of the SS pin.
If SS is configured as an output, the pin is a general output pin which does not affect the SPI
system. Typically, the pin will be driving the SS pin of the SPI Slave.
If SS is configured as an input, it must be held high to ensure Master SPI operation. If the SS pin
is driven low by peripheral circuitry when the SPI is configured as a Master with the SS pin
defined as an input, the SPI system interprets this as another master selecting the SPI as a
slave and starting to send data to it. To avoid bus contention, the SPI system takes the following
actions:
C Code Example
1. The MSTR bit in SPCR is cleared and the SPI system becomes a Slave. As a result of
2. The SPIF Flag in SPSR is set, and if the SPI interrupt is enabled, and the I-bit in SREG
void SPI_SlaveInit(void)
{
}
char SPI_SlaveReceive(void)
{
}
the SPI becoming a Slave, the MOSI and SCK pins become inputs.
is set, the interrupt routine will be executed.
/* Set MISO output, all others input */
DDR_SPI = (1<<DD_MISO);
/* Enable SPI */
SPCR = (1<<SPE);
/* Wait for reception complete */
while(!(SPSR & (1<<SPIF)))
/* Return Data Register */
return SPDR;
;
(1)
8008G–AVR–04/11