C8051F060DK Silicon Laboratories Inc, C8051F060DK Datasheet - Page 151

• Manufacturer Part Number: C8051F060DK
• Description: DEV KIT FOR F060/F062/F063
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F060DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F06x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F060
• Silicon Family Name: C8051F06x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051060, C8051F062 and C8051F063
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1214

C8051F060/1/2/3/4/5/6/7
13.3. Interrupt Handler
The CIP-51 includes an extended interrupt system supporting a total of 22 interrupt sources with two prior-
ity levels. The allocation of interrupt sources between on-chip peripherals and external inputs pins varies
according to the specific version of the device. Each interrupt source has one or more associated interrupt-
pending flag(s) located in an SFR. When a peripheral or external source meets a valid interrupt condition,
the associated interrupt-pending flag is set to logic 1.
If interrupts are enabled for the source, an interrupt request is generated when the interrupt-pending flag is
set. As soon as execution of the current instruction is complete, the CPU generates an LCALL to a prede-
termined address to begin execution of an interrupt service routine (ISR). Each ISR must end with an RETI
instruction, which returns program execution to the next instruction that would have been executed if the
interrupt request had not occurred. If interrupts are not enabled, the interrupt-pending flag is ignored by the
hardware and program execution continues as normal. (The interrupt-pending flag is set to logic 1 regard-
less of the interrupt's enable/disable state.)
Each interrupt source can be individually enabled or disabled through the use of an associated interrupt
enable bit in an SFR (IE-EIE2). However, interrupts must first be globally enabled by setting the EA bit
(IE.7) to logic 1 before the individual interrupt enables are recognized. Setting the EA bit to logic 0 disables
all interrupt sources regardless of the individual interrupt-enable settings.
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.
13.3.1. MCU Interrupt Sources and Vectors
The MCUs support 22 interrupt sources. Software can simulate an interrupt event by setting any interrupt-
pending 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,
associated vector addresses, priority order and control bits are summarized in Table 13.4. 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).
13.3.2. External Interrupts
The external interrupt sources (/INT0 and /INT1) are configurable as active-low level-sensitive or active-
low edge-sensitive inputs depending on the setting of bits IT0 (TCON.0) and IT1 (TCON.2). IE0 (TCON.1)
and IE1 (TCON.3) serve as the interrupt-pending flag for the /INT0 and /INT1 external interrupts, respec-
tively. If an /INT0 or /INT1 external interrupt is configured as edge-sensitive, the corresponding interrupt-
pending flag is automatically cleared by the hardware when the CPU vectors to the ISR. When configured
as level sensitive, the interrupt-pending flag follows the state of the external interrupt's input pin. The exter-
nal interrupt source must hold the input active until the interrupt request is recognized. It must then deacti-
vate the interrupt request before execution of the ISR completes or another interrupt request will be
generated.
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