| 摘要 |
An interface provides a DMA (direct memory access) data transfer between a microprocessor (9) and a computer (16). 8-bit data are transferred from the microprocessor data bus (12) via two data registers (20, 21), and 8-bit address-bytes from the microprocessor address bus (11) via two address registers (23, 24), to two respective computer buses (13, 14) and hence as 16-bit words onto the computer bus (15). A map key register (25) maps data signals supplied by the microprocessor (9) to computer memory addresses. A register (25) is provided for the reverse transfer information from the computer (16) to the microprocessor (9).
<??>A programmable read-only memory (64) is used to control the operation of the registers (20 to 25) such that an external transfer of information between the microprocessor (9) and the computer (16) is accomplished in response to internal instructions, such as a "block-move" instruction, of the microprocessor (9). |
