C8051F334-GMR Silicon Laboratories Inc, C8051F334-GMR Datasheet - Page 83

• Manufacturer Part Number: C8051F334-GMR
• Description: IC 8051 MCU 2K FLASH 20MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F33xr

Specifications of C8051F334-GMR

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, Temp Sensor, WDT
• Number Of I /o: 17
• Program Memory Size: 2KB (2K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 16x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QFN
• For Use With: 336-1451 - ADAPTER PROGRAM TOOLSTICK F330
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

C8051F330/1/2/3/4/5
EA = 0; // this is a dummy instruction with two-byte opcode.
; in assembly:
CLR EA ; clear EA bit.
CLR EA ; this is a dummy instruction with two-byte opcode.
If an interrupt is posted during the execution phase of a "CLR EA" opcode (or any instruction which clears
the EA bit), and the instruction is followed by a single-cycle instruction, the interrupt may be taken. How-
ever, a read of the EA bit will return a '0' inside the interrupt service routine. When the "CLR EA" opcode is
followed by a multi-cycle instruction, the interrupt will not be taken.
Some interrupt-pending flags are automatically cleared by the hardware when the CPU vectors to the ISR.
However, most are not cleared by the hardware and must be cleared by software before returning from the
ISR. If an interrupt-pending flag remains set after the CPU completes the return-from-interrupt (RETI)
instruction, a new interrupt request will be generated immediately and the CPU will re-enter the ISR after
the completion of the next instruction.
9.3.1. MCU Interrupt Sources and Vectors
The MCUs support 13 interrupt sources. Software can simulate an interrupt by setting any interrupt-pend-
ing flag to logic 1. If interrupts are enabled for the flag, an interrupt request will be generated and the CPU
will vector to the ISR address associated with the interrupt-pending flag. MCU interrupt sources, associ-
ated vector addresses, priority order and control bits are summarized in Table 9.4 on page 88. Refer to the
datasheet section associated with a particular on-chip peripheral for information regarding valid interrupt
conditions for the peripheral and the behavior of its interrupt-pending flag(s).
86
Rev. 1.7