M55800A Atmel Corporation, M55800A Datasheet - Page 54

• Manufacturer Part Number: M55800A
• Manufacturer: Atmel Corporation

Specifications of M55800A

• Flash (kbytes): 0 Kbytes
• Pin Count: 176
• Max. Operating Frequency: 33 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 58
• Ext Interrupts: 58
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Uart: 3
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 72
• Resistive Touch Screen: No
• Dac Channels: 1
• Dac Resolution (bits): 10
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Self Program Memory: NO
• External Bus Interface: 1
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.3/5.0
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

Programmer’s Model
2.6
2.6.1
2-8
Registers
The ARM-state register set
The ARM7TDMI processor has a total of 37 registers:
•
•
These registers are not all accessible at the same time. The processor state and operating
mode determine which registers are available to the programmer.
In ARM state, 16 general registers and one or two status registers are accessible at any
one time. In privileged modes, mode-specific banked registers become available. Figure
2-3 on page 2-10 shows which registers are available in each mode.
The ARM-state register set contains 16 directly-accessible registers, r0 to r15. A further
register, the CPSR, contains condition code flags and the current mode bits. Registers
r0 to r13 are general-purpose registers used to hold either data or address values.
Registers r14 and r15 have the following special functions:
Link register
Program counter
By convention, r13 is used as the Stack Pointer (SP).
In privileged modes, another register, the Saved Program Status Register (SPSR), is
accessible. This contains the condition code flags and the mode bits saved as a result of
the exception which caused entry to the current mode.
Banked registers are discrete physical registers in the core that are mapped to the
available registers depending on the current processor operating mode. Banked register
contents are preserved across operating mode changes.
31 general-purpose 32-bit registers
6 status registers.
Copyright © 1994-2001. All rights reserved.
Register 14 is used as the subroutine Link Register (LR).
Register r14 receives a copy of r15 when a Branch with Link (BL)
instruction is executed.
At all other times you can treat r14 as a general-purpose register.
The corresponding banked registers r14_svc, r14_irq, r14_fiq,
r14_abt and r14_und are similarly used to hold the return values
of r15 when interrupts and exceptions arise, or when BL
instructions are executed within interrupt or exception routines.
Register 15 holds the PC.
In ARM state, bits [1:0] of r15 are undefined and must be ignored.
Bits [31:2] contain the PC.
In Thumb state, bit [0] is undefined and must be ignored. Bits
[31:1] contain the PC.
ARM DDI 0029G