User`s guide

Introduction LZ87010 Advance User’s Guide
1-10 1/15/03
1.6.6 Interrupt Controller
The interrupt controller arbitrates between 13 interrupt sources, each with its own execution
vector. Each of these sources is assigned by software to one of four interrupt priority levels.
Eight external interrupt signals (INT[7:0]) are supported, sharing pins with Port 0. INT[0]
and INT[1] each have their own interrupt vector, while INT[7:2] share a single vector. For
these, the interrupt service routine identifies the asserted pin by reading Port 0 and scan-
ning for set bits. External interrupts can be selected to be edge-sensitive or level-sensitive.
NOTE: *The interrupt level shows the order in which simultaneous
interrupts will be serviced if they are all set to the same priority
level. The lowest level is serviced first. Levels 5 and 14 are not
implemented in the LZ87010.
1.6.7 External Program Memory Interface
The external program memory interface supports up to 64KB of off-chip memory that can
be used for both code and data. (Banking can extend this address space by using general-
purpose I/O pins to provide additional high-order address bits). The interface provides 16
address pins, 8 data pins, and two control pins: nPSEN and nPSWR (read and write
enables, respectively). It provides glueless support for static RAM, ROM, EPROM, and
EEPROM devices. The XMCFG register enables external memory access, determines
how much of the internal Flash will be replaced by external memory, and sets the number
of wait states.
The standard MOVC instruction allows software to read external program memory. An
extended instruction (
MOVC @(DPTR++),A) allows software to write it as well.
Table 1-2. Interrupt Sources and Vectors
DESCRIPTION
VECTOR
ADDRESS
INTERRUPT
LEVEL*
External Interrupt 0 (INT0 pin) 0x0003 0
Timer 0 0x000B 1
External Interrupt 1 (INT1 pin) 0x0013 2
Timer 1 0x001B 3
UART 0 0x0023 4
Timer 4/Timer 5 0x0033 6
Timer 2/Timer 3 0x003B 7
I
2
C0x00438
UART 1 0x004B 9
ADC 0x0053 10
DAC 0 Waveform Generator 0x005B 11
DAC 1 Waveform Generator 0x0063 12
External Interrupt 2 (INT7:2 pins) 0x006B 13