Rainbow Electronics AT90LS4433 User Manual
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AT90S/LS4433
1042G–AVR–09/02
Note:
1. Reserved and unused locations are not shown in the table.
All AT90S4433 I/Os and peripherals are placed in the I/O space. The I/O locations are
accessed by the IN and OUT instructions transferring data between the 32 general pur-
pose working registers and the I/O space. I/O Registers within the address range $00 -
$1F are directly bit-accessible using the SBI and CBI instructions. In these registers, the
value of single bits can be checked by using the SBIS and SBIC instructions. Refer to
the instruction set section for more details. When using the I/O specific commands IN
and OUT, the I/O addresses $00 - $3F must be used. When addressing I/O Registers as
SRAM, $20 must be added to this address. All I/O Register addresses throughout this
document are shown with the SRAM address in parentheses.
For compatibility with future devices, reserved bits should be written to zero when
accessed. Reserved I/O memory addresses should never be written.
Some of the Status Flags are cleared by writing a logical “1” to them. Note that the CBI
and SBI instructions will operate on all bits in the I/O Register, writing a one back into
any flag read as set, thus clearing the flag. The CBI and SBI instructions work with reg-
isters $00 to $1F only.
The I/O and Peripherals Control Registers are explained in the following sections.
$17 ($37)
DDRB
Data Direction Register, Port B
$16 ($36)
PINB
Input Pins, Port B
$15 ($35)
PORTC
Data Register, Port C
$14 ($34)
DDRC
Data Direction Register, Port C
$13 ($33)
PINC
Input Pins, Port C
$12 ($32)
PORTD
Data Register, Port D
$11 ($31)
DDRD
Data Direction Register, Port D
$10 ($30)
PIND
Input Pins, Port D
$0F ($2F)
SPDR
SPI I/O Data Register
$0E ($2E)
SPSR
SPI Status Register
$0D ($2D)
SPCR
SPI Control Register
$0C ($2C)
UDR
UART I/O Data Register
$0B ($2B)
UCSRA
UART Control and Status Register A
$0A ($2A)
UCSRB
UART Control and Status Register B
$09 ($29)
UBRR
UART Baud Rate Register
$08 ($28)
ACSR
Analog Comparator Control and Status Register
$07 ($27)
ADMUX
ADC Multiplexer Select Register
$06 ($26)
ADCSR
ADC Control and Status Register
$05 ($25)
ADCH
ADC Data Register High
$04 ($24)
ADCL
ADC Data Register Low
$03 ($23)
UBRRHI
UART Baud Rate Register High
Table 2. AT90S4433 I/O Space
(1)
(Continued)
I/O Address
(SRAM Address)
Name
Function