User's Manual

PMAC Dual-Ported RAM User Manual
Dual-Ported RAM Automatic Functions 29
Register Map
ASCII Host-to-PMAC Transfer
Address Description
0x062C
(Y:$D18B)
ASCII Host-Output Control Word
Bit 0: Host-Output-Control Flag
= 0: Host Output Enable. Set to 0 by PMAC when it has processed a command string.
= 1: Host Output Complete. Set to 1 by the Host when it has loaded a full command
string.
Bits 1-15: (Reserved for future use)
0x062E
(X:$D18B)
Bits 0-7: (Host-Output) Control character to be sent to PMAC
0x0630-
0x06CE
($D18C-
$D1B3)
Host-to-PMAC (Host-Output) Transfer Buffer -- Up to 159 characters with a NULL
character (ASCII value 0) terminating the string.
ASCII PMAC-to-Host Transfer
Address Description
0x06D0
(Y:$D1B4)
ASCII Host-Input Control Word (PMAC termination character)
Upper/Lower 8 of 16 bits(shown as hex digits):
00/00: PMAC Output Enable: Set to this value by HOST, to note that it has processed the
previous response data. PMAC will not update the Host Input buffer unless this control
word is zero.
00/0D: (<CR>) Set to this value by PMAC after it has filled the Host-Input buffer, to
note that there is more data to follow in transmission
01/0D: (<CR>) Set to this value by PMAC after it has filled the Host-Input buffer, to
note a PMAC program "CMD" command response - End of transmission; no ACK is sent
02/0D: (<CR>) Set to this value by PMAC after it has filled the Host-Input buffer, to
note a PMAC program "SEND" command message - End of transmission; No ACK is
sent
8d/dd: Set to this value by PMAC to note an error in the command; where "ddd" = 12-bit
BCD-coded Error Number (See I6 description for error listing)
0x06D2
(X:$D1B4)
(# of ASCII characters + 1) in the Host-Input buffer; set by PMAC after it has written to
the buffer
0x06D4-
0x07D2
($D1B5-
D1F4)
PMAC-to-Host (Host-Input) Transfer Buffer --Up to 255 characters with a NULL
character (ASCII value 0) terminating the string.
There are two ASCII character bytes per 16-bit register in DPRAM. The first character of the pair is in the
LSB. This format should be convenient for host computers with Intel processors, but probably will require
a byte swap for host computers with Motorola processors.
Binary Rotary Program Buffers
The Binary Rotary Program Buffers in PMAC’s DPRAM allows the host computer to send program
commands to PMAC in binary format for the fastest possible transmission of these commands. A standard
rotary program buffer must be established in PMAC's internal memory with the DEFINE ROTARY
command, as well as a buffer in DPRAM for the binary transmission from the host. Only the first of two
binary rotary buffers that PMAC supports in DPRAM is described here. Call or fax Delta Tau if the
details (memory register address/description) for the second one are required.