aduc844bs62-5 Analog Devices, Inc., aduc844bs62-5 Datasheet - Page 17

• Manufacturer Part Number: aduc844bs62-5
• Description: Microconverter 1-cycle 8052 24-bit 16-bit 12-bit K-byte Flash
• Manufacturer: Analog Devices, Inc.

INTRODUCTION
The ADuC844 is a pin compatible upgrade to the ADuC834
provide increased core performance. The ADUC844 has a single
cycle 8052 core allow operation at up to 12.58MIPs. It has all the
same features as the ADuC834 but the standard 12-cycle 8052 core
has been replaced with a 12.6MIPs single cycle core.
Since the ADuC844 and ADuC834 share the same feature set only
the differences between the two chips are documented here. For full
documentation on the ADuC834 please consult the datasheet
available at http://www.analog.com/microconverter
8052 Instruction Set
The following pages document the number of clock cycles required
for each instruction. Most instructions are executed in one or two
clock cycles resulting in 12.6MIPs peak performance when
operating at PLLCON = 00H.
Timer Operation
Timers on a standard 8052 increment by one with each machine
cycle. On the ADuC842 one machine cycle is equal to one clock
cycle hence the timers will increment at the same rate as the core
clock.
INSTRUCTION TABLE
REV. PrB
ARITHMETIC
ADD A,Rn
ADD A,@Ri
ADDC A,Rn
ADDC A,@Ri
ADD A,dir
ADD A,#data
SUBB A,Rn
SUBB A,@Ri
SUBB A,dir
SUBB A,#data
INC A
INC Rn
INC @Ri
INC dir
INC DPTR
DEC A
DEC Rn
DEC @Ri
DEC dir
MUL AB
DIV AB
DA A
Mnemonic Arithmetic
PRELIMINARY TECHNICAL DATA
TABLE IV: Optimized Single Cycle 8051 Instruction Set
Add register to A
Add indirect memory to A
Add register to A with carry
Add indirect memory to A with carry
Add direct byte to A
Add direct byte to A with carry
Subtract register from A with borrow
Subtract indirect memory from A with borrow
Subtract direct from A with borrow
Subtract immediate from A with borrow
Increment A
Increment register
Increment indirect memory
Increment direct byte
Increment data pointer
Decrement A
Decrement Register
Decrement indirect memory
Decrement direct byte
Multiply A by B
Divide A by B
Decimal Adjust A
-17-
Description
ALE
The output on the ALE pin on the ADuC834 was a clock at 1/6th of
the core operating frequency. On the ADuC844 the ALE pin
operates as follows.
For a single machine cycle instruction: ALE is high for the first half
of the machine cycle and low for the second half. The ALE output
is at the core operating frequency.For a two or more machine cycle
instruction: ALE is high for the first half of the first machine cycle
and then low for the rest of the machine cycles.
External Memory Access
There is no support for external program memory access on the
ADuC844. When accessing external RAM the EWAIT register may
need to be programmed in order to give extra machine cycles to
MOVX commands. This is to account for differing external RAM
access speeds.
Bytes
1
1
1
1
2
2
1
1
2
1
1
1
1
2
1
1
1
1
2
1
1
1
ADuC844
Cycles
1
2
1
2
2
2
1
2
2
1
1
1
2
2
3
1
1
2
2
9
9
2