C8051F021 Silicon Laboratories Inc, C8051F021 Datasheet - Page 254

• Manufacturer Part Number: C8051F021
• Description: IC 8051 MCU 64K FLASH 64TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F02xr

Specifications of C8051F021

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: EBI/EMI, SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 4.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x8b, 8x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

C8051F020/1/2/3
23.2.2. Software Timer (Compare) Mode
In Software Timer mode, the PCA0 counter/timer is compared to the module's 16-bit capture/compare register
(PCA0CPHn and PCA0CPLn). When a match occurs, the Capture/Compare Flag (CCFn) in PCA0CN is set to logic
1 and an interrupt request is generated if CCF interrupts are enabled. The CCFn bit is not automatically cleared by
hardware when the CPU vectors to the interrupt service routine, and must be cleared by software. Setting the ECOMn
and MATn bits in the PCA0CPMn register enables Software Timer mode.
Important Note About Capture/Compare Registers: When writing a 16-bit value to the PCA0 Capture/Compare
registers, the low byte should always be written first. Writing to PCA0CPLn clears the ECOMn bit to ‘0’; writing to
PCA0CPHn sets ECOMn to ‘1’.
254
PCA0CPLn
Write to
Reset
PCA0CPHn
Write to
0
1
ENB
ENB
Figure 23.5. PCA Software Timer Mode Diagram
W
M
P
1
6
n
x
C
O
M
E
n
PCA0CPMn
C
A
P
P
n
0 0
C
N
A
P
n
M
A
T
n
O
G
T
n
0 0
W
M
P
n
C
C
E
F
n
x
Enable
PCA
Timebase
Rev. 1.4
PCA0CPLn
PCA0L
16-bit Comparator
PCA0CPHn
PCA0H
Match
C
F
C
R
0
1
PCA0CN
C
C
F
4
C
C
F
3
C
C
F
2
C
C
F
1
PCA Interrupt
C
C
F
0