Intel 8XC251SA, User Manual

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13-17
EXTERNAL MEMORY INTERFACE
13.7.2 Port 0 and Port 2 Pin Status in Page Mode
In a page-mode bus cycle, the data is multiplexed with the upper address byte on port 2. However,
if the instruction uses an 8-bit address (e.g., MOVX @Ri), the contents of P2 are driven onto the
pins when data is not on the pins. These logic levels can be used to select 256-bit pages in external
memory. During bus idle, the port 0 and port 2 pins are held at high impedance.
(For port pin status when the chip in is idle mode, powerdown mode, or reset, see Chapter 12,
“Special Operating Modes.”)