1
This is a short description of the demo layout, a 68HC11 module which
2
supports a Toshiba LCD display (160x128 pixels) with a single power supply
3
of 5V (plus backup if you want). There is another example, LED, which doesn't
4
have an accompanying schematic or description, but it's layout uses a number
5
of the modern features of pcb. It does include a netlist file for experimenting
6
with the rats nest feature.
8
The 6811 example is old, and was a home-made board - it has some features
9
that make it unsuitable for conventional manufacture without making some
11
The board was originally designed as a control unit for some analog
12
amplifiers. For this reason only a few ports are available at the connectors.
14
Drop me a line if you need additional information like bootloader...
16
The scematics are in demo.fig (xfig format)
25
25k Tr1 (voltage regulator of LCD display)
26
50k Tr2 (selects level of 'low batterie' signal,
27
be careful with range)
44
RTC62421 real-time clock
47
MAX680 step-up converter
48
MAX691 uP supervisor chip
50
LCD Toshiba LCD TLX-1013-E0 display
60
0x4000-0x4fff real-time clock A0-A3 select registers
61
0x5000-0x5fff latch, all addresses are equivalent
62
0x6000-0x6fff LCD display;
63
A0==0 data access, A0==1 command access
64
0x8000-0xbfff 8kb segment of RAM, segment number is determined
65
by port PA4-PA6 of CPU
68
PA0, PA1 unused, pulled up
69
PA2 low batterie indicator input
71
write 1 to switch on or 0 (power up default) for off
72
PA4-6 segment selector of static RAM
73
PA7 beeper output (low active at T2)
76
PC0-7 address/data bus
80
PD2 RS232 shutdown (==0 for shutdown mode)
81
PD3-5 connected to analog connector
84
PE4-7 connected to analog connector
87
J1 selects between 128kb and 32kb static RAM;
88
close for 32kb circuits and for some 128kb
89
J2,J3 determine operation mode of CPU (see 68HC11 manual);
90
close both for bootstrap mode,
91
open both for normal operation