ATMEGA162V-1PC Atmel, ATMEGA162V-1PC Datasheet - Page 32

• Manufacturer Part Number: ATMEGA162V-1PC
• Description: IC MCU AVR 16K 1.8V 8MHZ 40-DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA162V-1PC

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 1MHz
• Connectivity: EBI/EMI, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Data Converters: -

Using all 64KB Locations of
External Memory
32
ATmega162(V/U/L)
Since the external memory is mapped after the internal memory as shown in Figure 11,
only 64,256 Bytes of external memory are available by default (address space 0x0000
to 0x05FF is reserved for internal memory). However, it is possible to take advantage of
the entire external memory by masking the higher address bits to zero. This can be
done by using the XMMn bits and control by software the most significant bits of the
address. By setting Port C to output 0x00, and releasing the most significant bits for nor-
mal Port Pin operation, the Memory Interface will address 0x0000 - 0x1FFF. See code
example below.
Note:
Care must be exercised using this option as most of the memory is masked away.
Assembly Code Example
C Code Example
#define OFFSET 0x2000
void XRAM_example(void)
{
unsigned char *p = (unsigned char *) (OFFSET + 1);
DDRC = 0xFF;
PORTC = 0x00;
SFIOR = (1<<XMM1) | (1<<XMM0);
*p = 0xaa;
SFIOR = 0x00;
*p = 0x55;
}
; OFFSET is defined to 0x2000 to ensure
; external memory access
; Configure Port C (address high byte) to
; output 0x00 when the pins are released
; for normal Port Pin operation
ldi
out
ldi
out
; release PC7:5
ldi
out
; write 0xAA to address 0x0001 of external
; memory
ldi
sts
; re-enable PC7:5 for external memory
ldi
out
; store 0x55 to address (OFFSET + 1) of
; external memory
ldi
sts
1. The example code assumes that the part specific header file is included.
r16, 0xFF
DDRC, r16
r16, 0x00
PORTC, r16
r16, (1<<XMM1)|(1<<XMM0)
SFIOR, r16
r16, 0xaa
0x0001+OFFSET, r16
r16, (0<<XMM1)|(0<<XMM0)
SFIOR, r16
r16, 0x55
0x0001+OFFSET, r16
(1)
(1)
2513C–AVR–09/02