AT90CAN32 Automotive Atmel Corporation, AT90CAN32 Automotive Datasheet - Page 20

• Manufacturer Part Number: AT90CAN32 Automotive
• Manufacturer: Atmel Corporation

Specifications of AT90CAN32 Automotive

• Flash (kbytes): 32 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 53
• Ext Interrupts: 8
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 2
• Can: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 125
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 8
• Input Capture Channels: 2
• Pwm Channels: 7
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

4.2.1
SRAM Data Access
When the addresses accessing the SRAM memory space exceeds the internal data memory
locations, the external data SRAM is accessed using the same instructions as for the internal
data memory access. When the internal data memories are accessed, the read and write strobe
pins (PG0 and PG1) are inactive during the whole access cycle. External SRAM operation is
enabled by setting the SRE bit in the XMCRA Register.
Accessing external SRAM takes one additional clock cycle per byte compared to access of the
internal SRAM. This means that the commands LD, ST, LDS, STS, LDD, STD, PUSH, and POP
take one additional clock cycle. If the Stack is placed in external SRAM, interrupts, subroutine
calls and returns take three clock cycles extra because the two-byte program counter is pushed
and popped, and external memory access does not take advantage of the internal pipe-line
memory access. When external SRAM interface is used with wait-state, one-byte external
access takes two, three, or four additional clock cycles for one, two, and three wait-states
respectively. Interrupts, subroutine calls and returns will need five, seven, or nine clock cycles
more than specified in the instruction set manual for one, two, and three wait-states.
The five different addressing modes for the data memory cover: Direct, Indirect with Displace-
ment, Indirect, Indirect with Pre-decrement, and Indirect with Post-increment. In the Register
File, registers R26 to R31 feature the indirect addressing pointer registers.
The direct addressing reaches the entire data space.
The Indirect with Displacement mode reaches 63 address locations from the base address given
by the Y- or Z-register.
When using register indirect addressing modes with automatic pre-decrement and post-incre-
ment, the address registers X, Y, and Z are decremented or incremented.
The 32 general purpose working registers, 64 I/O Registers, 160 Extended I/O Registers, and
the “ISRAM size” bytes of internal data SRAM in the AT90CAN32/64/128 are all accessible
through all these addressing modes. The Register File is described in
“General Purpose Regis-
ter File” on page
12.
AT90CAN32/64/128
20
7682C–AUTO–04/08