https://www.hobbyprojects.com/8051_tutorial/acall_absolute_call.html
I was learning about acall on the above website, but then came across the term page. What exactly is a page?
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3\$\begingroup\$ Try expanding your google search from "page", to "memory page". \$\endgroup\$– efox29Commented Mar 28, 2020 at 18:45
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1\$\begingroup\$ The 8051 micro can only address 64K of memory. In simple terms, f you need more an output pin can be used to connect another 64K of memory, another "bank" or page. \$\endgroup\$– skveryCommented Mar 28, 2020 at 20:38
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In short, and in this context, the whole 11-bit address area that is accessible with the ACALL instruction is divided to eight areas called pages that are 256 bytes each.
As the ACALL opcode follows only a single byte which defines the 8 least significant bits of the address, there needs to be 8 different ACALL opcodes that define the high 3 bits - the page.
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1\$\begingroup\$ I think you mean "eight" different opcodes to provide the upper three bits. Or else just one opcode with an assembler option to specify the upper three bits into the opcode. \$\endgroup\$– jonkCommented Mar 28, 2020 at 19:18
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1\$\begingroup\$ The ACALL opcode will be followed by a byte containing the 8 least significant bits of the destination address. \$\endgroup\$ Commented Mar 28, 2020 at 19:43
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