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13.11.2 Interrupt Register The QADC64 interrupt register QADC64INT specifies the priority level of QADC64 interrupt requests The values contained in the IRL1 and IRL2 fields in QADC64INT determine the priority of QADC64 interrupt service requests.The interrupt levels for queue 1 and queue 2 may be different. 13.11.3 Interrupt Levels and Time Multiplexing The QADC64 conditionally generates interrupts to the bus master via the IMB IRQ signals. When the QADC64 sets a status bit assigned to generate an interrupt, the QADC64 drives the IRQ bus. The value driven onto IRQ[7:0] represents the interrupt level assigned to the interrupt source. Under the control of ILBS, each interrupt request level is driven during the time multiplexed bus during one of four different time slots, with eight levels communicated per time slot. No hardware priority is assigned to interrupts. Furthermore, if more than one source on a module requests an interrupt at the same level, the system software must assign a priority to each source requesting at that level. Figure 13-11 displays the interrupt levels on IRQ with ILBS. IMB3 CLOCK ILBS [1:0] 00 IMB3 IRQ [7:0] 01 IRQ 0:7 10 IRQ 8:15 11 00 01 IRQ 16:23 IRQ 24:31 IRQ 0:7 10 11 Figure 13-11 Interrupt levels on IRQ with ILBS 13.12 Programming Model Each QADC64 occupies 1 Kbyte (512 16-bit entries) of address space. The address space consists of ten 16-bit control, status, and port registers; 64 16-bit entries in the CCW table; and 64 16-bit entries in the result table. The result table occupies 192 16bit address locations because the result data is readable in three data alignment formats. Table 13-6 shows the QADC64 memory map. The lowercase “x” appended to each register name represents “A” or “B” for the QADC64_A or QADC64_B module, respectively. The address offset shown is from the base address of the module. Refer to 1.3 MPC555 Address Map to locate each QADC64 module in the MPC555 memory map. MPC555 USER’S MANUAL QUEUED ANALOG-TO-DIGITAL CONVERTER MODULE-64 Revised 15 September 1999 MOTOROLA 13-30