Click here for a list of the parts required to build an SC132, v1.0, Z80 SIO/0 Module.
Experienced builders just go ahead and populate the board. There shouldn’t be any further surprises to catch you out.
Introduction
This guide assumes you are familiar with assembling circuit boards, soldering, and cleaning. If not, it is recommended you read some of the guides on the internet before continuing.
First check you have all the required components, as listed in the parts list.
Before assembling it is worth visually inspecting the circuit board for anything that looks out of place, such as mechanical damage or apparent manufacturing defects.
If you have a multimeter that measures resistance or has a continuity test function, check there is not a short on the power supply tracks. Connect the probes to each terminal of one of the capacitors, such as C1. This should be an open circuit, not a short.
The picture below shows what a completed SC132, Z80 SIO/0 module should look like.
Resistors 2k2
Fit and solder the 2k2 resistors R1 to R8 (shown below in red).
These can be fitted either way around, as they are not polarity dependent.
Resistors 100k
Fit and solder the 100k resistors R9 to R12.
Resistors 10k
Fit and solder the 10k resistor R13.
IC sockets
Fit and solder the IC sockets.
Be sure to fit them with the notch matching the legend on the circuit board, so you do not end up fitting the IC the wrong way around too.
Headers (angled, single row)
Fit and solder header pins P2, P3, and P4.
This can be either a single strip of 16 pins with two pins removed, as illustrated the photo at the start of this page, or as three separate strips.
Header (angled, double row)
Fit and solder header pins P1.
Some pins need to be removed to match the holes in the PCB.
Quick Test
It is now worth repeating the check made earlier for a short on the power supply tracks. Connect the meter probes to each terminal of one of the capacitors, such as C1. This should be an open circuit, not a short.
Capacitors 100 nF
Fit and solder capacitors C1 to C6.
These capacitors can be fitted either way around, as they are not polarity dependent.
The exact value of this component is not critical. The use of very cheap capacitors within the range of about 50 to 100 nF is acceptable.
Quick Test
Again, repeat the check made earlier for a short on the power supply tracks. Connect the meter probes to IC U1 pin 16 (shown below in red) and U1 pin 8 (shown in green). This should be an open circuit, not a short. If you are using a digital meter set to measure resistance it will likely take a few seconds for the reading to stabilise as there are now capacitors on the power lines. A reading of more than 100 kΩ (100000 ohms) is acceptable.
Headers (straight, single row)
Fit and solder the pin header JP11, 1 row of 3 pins.
Fit and solder the pin headers JP3 and JP4, 1 row of 2 pins each.
These header pins may need to be cut from longer strips using wire cutters to cut the plastic.
Headers (straight, double row)
Fit and solder the pin header JP5 and JP6, 2 rows of 3 pins each.
Fit and solder the pin header JP7 plus JP8 plus JP9 plus JP10, a single 2 row of 4 pin header.
Fit and solder the pin header JP1 plus JP2, a single 2 row of 2 pin header.
These header pins may need to be cut from longer strips using wire cutters to cut the plastic.
Quick Tests
Repeat the check made earlier for a short on the power supply tracks. Connect the meter probes to IC U1 pin 16 (shown below in red) and U1 pin 8 (shown in green). This should be an open circuit, not a short. If you are using a digital meter set to measure resistance it will likely take a few seconds for the reading to stabilise as there are now capacitors on the power lines. A reading of more than 100k Ω (100000 ohms) is acceptable.
Measure the resistance between U1 pin 16 (red) and U2 pin 6 (blue). This should be 10k ohms. Anything from 9k to 11k is acceptable.
Measure the resistance between U1 pin 16 (red) and the RxD pin of P2 and P3 (brown). These should be 100k ohms. Anything from 90k to 110k is acceptable.
Measure the resistance between U1 pin 8 (green) and the CTS pin of P2 and P3 (orange). These should be 100k ohms. Anything from 90k to 110k is acceptable.
Inspection
Remove any solder ‘splats’ with a brush, such as an old toothbrush.
Visually inspect the soldering for dry joints and shorts.
Clean the flux off with suitable cleaning materials.
Visually inspect again.
Integrated Circuits
If all the above tests check out okay, insert the integrated circuits into their sockets.
Initial Testing
Fit a jumper shunts in the positions shown below.
Insert the module into an RC2014 compatible backplane. The backplane should also include a CPU, ROM, RAM, clock, and reset. The ROM should contain firmware that supports a Z80 SIO serial port. This test assumes the system has a 7.3728 MHz main clock.
Connect an FTDI style serial cable to Port A (P2) and connect the other end to a computer running terminal emulations software. The terminal should be set to 115200 baud, 8 data bits, 1 stop bit, no parity, no flow control (at least for this initial test).
Power up and hopefully your terminal will display an appropriate startup message.
If you have further problem the SC132 troubleshooting guide may help.
Getting Started
The SC132 User Guide can be found here.
Other information about SC132 can be found here.
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