C8051F131R Silicon Labs, C8051F131R Datasheet - Page 165

• Manufacturer Part Number: C8051F131R
• Description: 8-bit Microcontrollers - MCU 128kB 100MIPS 8448B RAM
• Manufacturer: Silicon Labs

Specifications of C8051F131R

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 100 MHz
• Program Memory Size: 128 KB
• Data Ram Size: 8.25 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.7 V to 3.6 V
• Package / Case: TQFP-64
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 9
• Data Rom Size: 64 KB
• Interface Type: I2C, SMBus, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 32
• Number Of Timers: 16 bit
• Processor Series: C8051
• Program Memory Type: Flash
• Factory Pack Quantity: 500
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 3 V

12. Multiply And Accumulate (MAC0)
The C8051F120/1/2/3 and C8051F130/1/2/3 devices include a multiply and accumulate engine which can
be used to speed up many mathematical operations. MAC0 contains a 16-by-16 bit multiplier and a 40-bit
adder, which can perform integer or fractional multiply-accumulate and multiply operations on signed input
values in two SYSCLK cycles. A rounding engine provides a rounded 16-bit fractional result after an addi-
tional (third) SYSCLK cycle. MAC0 also contains a 1-bit arithmetic shifter that will left or right-shift the con-
tents of the 40-bit accumulator in a single SYSCLK cycle. Figure 12.1 shows a block diagram of the MAC0
unit and its associated Special Function Registers.
12.1. Special Function Registers
There are thirteen Special Function Register (SFR) locations associated with MAC0. Two of these regis-
ters are related to configuration and operation, while the other eleven are used to store multi-byte input
and output data for MAC0. The Configuration register MAC0CF (SFR Definition 12.1) is used to configure
and control MAC0. The Status register MAC0STA (SFR Definition 12.2) contains flags to indicate overflow
conditions, as well as zero and negative results. The 16-bit MAC0A (MAC0AH:MAC0AL) and MAC0B
(MAC0BH:MAC0BL) registers are used as inputs to the multiplier. The MAC0 Accumulator register is 40
bits long, and consists of five SFRs: MAC0OVR, MAC0ACC3, MAC0ACC2, MAC0ACC1, and
MAC0ACC0. The primary results of a MAC0 operation are stored in the Accumulator registers. If they are
needed,
(MAC0RNDH:MAC0RNDL).
the
rounded
MAC0OVR
1 bit Shift
MAC0CF
MAC0AH
MAC0 A Register
results
MAC0FM
Figure 12.1. MAC0 Block Diagram
MAC0ACC3
are
MAC0AL
MAC0RNDH
16 x 16 Multiply
MAC0 Rounding Register
stored
MAC0 Accumulator
Rounding Engine
MAC0ACC2
40 bit Add
Rev. 1.4
MAC0BH
in
MAC0 B Register
MAC0RNDL
C8051F120/1/2/3/4/5/6/7
the
MAC0ACC1
16-bit
MAC0BL
1
0
MAC0MS
C8051F130/1/2/3
Rounding
MAC0STA
Flag Logic
0
MAC0ACC0
Register
MAC0RND
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