Subj : Re: Plus 4 rom error - is there any place to report it?
To   : All
From : George
Date : Sun Nov 28 2021 05:51 pm

If anyone has a Plus/4 and has nothing better to do, it would be helpful if
you could run the programs listed below and report the results.  The
programs report the total number of ACIA interrupts which occur while
transmitting 256 bytes of data continuously at 2400 baud.  They should be
run with nothing plugged into the User Port - no modem or anything.

My suspicion is that the single-byte transmit buffer of the Plus/4 results
in back-to-back double interrupts being generated for each byte
transmitted, which can cause problems at high speed.  If that's the case,
the first program will report about 512 interrupts, and the second about
256.  But there may be no difference.  Anyway, I just need to know.

irqtest1
--------

10 rem  irq test1 to count interrupts
20 cb = 819
30 for i = 0 to 161
40 read a
50 poke cb+i,a
60 next
70 sys cb
75 open 2,2,0,chr$(26)+chr$(7)
80 sys 940
85 close 2
90 sys 845
95 print peek(1009)*256 + peek(1008)
100 data 120,32,85,252,186,202,189,0
110 data 1,24,105,36,141,20,3,232
120 data 189,0,1,105,0,141,21,3
130 data 88,96,120,169,14,141,20,3
140 data 169,206,141,21,3,88,96,173
150 data 9,255,41,2,240,3,32,96
160 data 206,44,216,7,16,64,173,1
170 data 253,141,212,7,16,56,238,240
180 data 3,208,3,238,241,3,173,212
190 data 7,41,8,240,24,173,212,7
200 data 41,247,141,212,7,173,0,253
210 data 141,213,7,173,211,7,201,63
220 data 240,3,32,220,234,173,212,7
230 data 41,16,240,10,44,206,7,16
240 data 5,162,0,32,131,234,76,43
250 data 206,120,169,0,141,240,3,141
260 data 241,3,141,242,3,88,44,206
270 data 7,48,251,169,85,141,205,7
280 data 56,110,206,7,206,242,3,208
290 data 237,173,2,253,73,12,141,2
300 data 253,96

irqtest2
--------

10 rem  irq test2 to count interrupts
20 cb = 819
30 for i = 0 to 173
40 read a
50 poke cb+i,a
60 next
70 sys cb
75 open 2,2,0,chr$(26)+chr$(7)
80 sys 952
85 close 2
90 sys 845
95 print peek(1009)*256 + peek(1008)
100 data 120,32,85,252,186,202,189,0
110 data 1,24,105,36,141,20,3,232
120 data 189,0,1,105,0,141,21,3
130 data 88,96,120,169,14,141,20,3
140 data 169,206,141,21,3,88,96,173
150 data 9,255,41,2,240,3,32,96
160 data 206,44,216,7,16,76,173,1
170 data 253,141,212,7,16,68,238,240
180 data 3,208,3,238,241,3,173,212
190 data 7,41,8,240,24,173,212,7
200 data 41,247,141,212,7,173,0,253
210 data 141,213,7,173,211,7,201,63
220 data 240,3,32,220,234,173,212,7
230 data 41,16,240,22,44,206,7,16
240 data 17,172,2,253,152,73,12,141
250 data 2,253,162,0,32,131,234,140
260 data 2,253,76,43,206,120,169,0
270 data 141,240,3,141,241,3,141,242
280 data 3,88,44,206,7,48,251,169
290 data 85,141,205,7,56,110,206,7
300 data 206,242,3,208,237,173,2,253
310 data 73,12,141,2,253,96
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