BG49792A1 - Device for controlling the access to common resources of microprocessor z80 and personal computer - Google Patents

Abstract

The device is used in computing technology and ensures normal uploading of all address areas in the common resource of a dynamic memory with a capacity over 64 kbit. The device contains an arbitrator block (1) for access control to the common dynamic memory (2), control (9) and address (3) bus, input/output highway (4) of the personal computer (5), two address multiplexers (6 and 7) and a multiplexer address bus (8). The control outputs (10) of the microprocessor Z80 (11) are connected to the arbitrator block (1) and to inputs (29 and 30) of the modification block of a junior address bus (28), and the outputs (13, 14, 15, 16 and 17) of the arbitration block (1) are connected respectively to the inputs "reset" and "busreq" of the microprocessor Z80 (11), with the inputs "ras", "cas" and "wr" of the common dynamic memory (2), with the inputs "E" and "S" of the two address multiplexers (6 and 7) and with inputs of the modification block of the junior address bus (28). Output (12) of the arbitration block (1) is connected with the input line "RDY" for readiness of the input/output highway (4); two outputs (23 and 24) are connected to the data buffer (21) and one output (25) for address control - to the multiplexers (6 and 7). The address lines from A8 to A15 (26) of the microprocessor Z80 (11) are connected to the second address multiplexer (7), and address lines from A0 to A8 (27) - to the modification block of junior address bus (28), and the block outputs (31) are connected with the remaining address inputs of the second address multiplexer (7). Through the first bi-directional data bus (20) the microprocessor Z80 (11) is connected to the common dynamic memory (2) and to the data buffer (21), which is connected through a second data bus (22) to input/output highway (4).