RLV12 V2.0 Building Instructions


The RLV12 Emulator Version 2.0 consists of a short dual-width Q-Bus card and a breakout board. The two prints are connected via a 34-pin ribbon cable. The break-out board has the SD-Card cage, the AVR ISP Header and the Atmel CPLD JTAG interface. It also brings the serial port from the MCU either directly as TTL signals to a 4-pin header or via a MAX232 levelshifter to a connector.

The layout has been designed to fit on a filler panel of a BA23 case. When using the MAX232 you must add a DB-9 connector to the filler panel and wire the pins 2,3 and 5 with the connector that carries the signal from/to the MAX232 RS-232 level shifter. Please make sure to place RX and TX according the type of connector, male or female, you are using.

BOM Bill of Materials

Name Value Package Description
C1 330n C0805 Decoupling Capacitor
C2 330n C0805 Decoupling Capacitor
C3 330n C0805 Decoupling Capacitor
C4 1u C0805 Decoupling Capacitor
C5 220n C0805 Decoupling Capacitor
C6 220n C0805 Decoupling Capacitor
C7 220n C0805 Decoupling Capacitor
C8 220n C0805 Decoupling Capacitor
C9 22p C0805 X-TAL Load Capacitor
C10 22p C0805 X-TAL Load Capacitor
C11 220n C0805 Decoupling Capacitor
C12 220n C0805 Decoupling Capacitor
C13 220n C0805 Decoupling Capacitor
C14 220n C0805 Decoupling Capacitor
C15 220n C0805 Decoupling Capacitor
C16 220n C0805 Decoupling Capacitor
C17 220n C0805 Decoupling Capacitor
C18 220n C0805 Decoupling Capacitor
C19 330n C0805 Decoupling Capacitor
C20 330n C0805 Decoupling Capacitor
C21 47u SMC_C Decoupling Capacitor
C22 47u SMC_C Decoupling Capacitor
C23 47u SMC_C Decoupling Capacitor
C24 220n C0805 Decoupling Capacitor
C25 220n C0805 Decoupling Capacitor
C26 220n C0805 Decoupling Capacitor
C27 220n C0805 Decoupling Capacitor
C28 47u E2,5-5 Decoupling Capacitor
C29 47u E2,5-5 Decoupling Capacitor
C30 47u E2,5-5 Decoupling Capacitor
C31 47u E2,5-5 Decoupling Capacitor
C32 47u E2,5-5 Decoupling Capacitor
C33 47u E2,5-5 Decoupling Capacitor
C34 330n C0805 Decoupling Capacitor
C35 330n C0805 Decoupling Capacitor
C36 330n C0805 Decoupling Capacitor
E1 74S38N DIL14 Quad O.C. NAND Gate
E2 74S38N DIL14 Quad O.C. NAND Gate
E3 74S38N DIL14 Quad O.C. NAND Gate
E4 74S38N DIL14 Quad O.C. NAND Gate
IC1 ATF1504AS-10JU44 PLCC-44 64 Macrocell CPLD
IC2 74C4049N DIL16 Hex High-Voltage Input Buffer
IC3 74C4049N DIL16 Hex High-Voltage Input Buffer
IC4 74C4049N DIL16 Hex High-Voltage Input Buffer
IC6 74C4049N DIL16 Hex High-Voltage Input Buffer
IC7 74C4049N DIL16 Hex High-Voltage Input Buffer
IC8 ATMEGA1284P-20PU DIL40 Microcontroller
IC9 ATF1508AS-10JU84 PLCC-84 128 Macrocell CPLD
IC10 REG1117 SOT223 3V3 LDO Voltage Regulator
IC11 74S38N DIL14 Quad O.C. NAND Gate
IC12 74S38N DIL14 Quad O.C. NAND Gate
IC13 74S38N DIL14 Quad O.C. NAND Gate
IC14 74S38N DIL14 Quad O.C. NAND Gate
Q1 22.1184MHz HC49/S X-TAL
R1 680Ω M0805 Bus Signal Termination Resistor
R2 330Ω M0805 Bus Signal Termination Resistor
R3 680Ω M0805 Bus Signal Termination Resistor
R4 330Ω M0805 Bus Signal Termination Resistor
SV1 BREAKOUT ML34L Male 34-PIN IDC Header Angled


As always start with the SMD/SMT parts. In this versions only the resistors, most capacitors and the LDO Voltage regulator are SMD/SMT parts. However all these devices are easy to solder.

For the CPLDs in PLCC package you must use through hole PLCC sockets. The ATF1504 requires a PLCC-44 and the ATF1508 requires a PLCC-84 sockets.

All other ICs can be soldered directly but you can use DIP sockets if you like.

The IDC-34 header is a shrouded angled version. You also need to build a break-out board and connect the emulator with the break-out board via a 34-pin ribbon cable.

Completed Emulator

Here you can see the fully assembled and populated RLV12 Emulator V2.0. As you can see I have used sockets for all ICs on the top layer.

Emulator Top View

The bottom layer carries the 3V3 LDO regulator and some SMD capacitors. It is very important that only low-profile devices are soldered to the bottom side of the PCB. The specs for Q-Bus cards says no more than 1.6mm.

Emulator Bottom View

Activty LED

In order to have the activity LED you need to add a wire to the RLV12 Emulator V2.0 board. The wire goes from PIN 20 of the MCU to PIN 18 of the IDC-34 pin-header. You just need to add the wire, there are no other wires to cut, the correpsonding input of the CPLD is no longer active.

Activity LED

Programming the MCU

The break-out board has a standard Atmel ISP header to program the MCU. This is the 6-pin IDC header on the break-out board. Programming AVR MCUs can sometimes be confusing as there are several settings that must be correct. Also there are three areas that can/must be programmed.

The first challenge is when programming a new completely erased AVR microcontroller. In this state the internal 8MHz RC oscillator is activated from which the CPU clock is derived and in addition the system clock prescaler is activated and devides the RC clock by 8. So in fact the CPU is clocked only 1MHz. As the ISP clock rate must be no higher than ΒΌ of the CPU clock this means before you program the MCU you need to set the clock rate of the IPS programmer to be 250kHz or less. I always use a very low rate.

The first thing you should do is set the device type and check the signature. This is just to verify that we have inserted the correct MCU model into the emulator. In our case the device is a ATmega1248P

Once you have checked the correct signature you should program the fuses.

I normally use AVR Studio 4.19 to program my AVR microcontrollers. But to give you a better view of the required settings here a screenshot of AVRFuses

AVR Fuses

Make sure you have selected the same fuses as you can see in the picture. You can also use the hex values shown at the bottom of the screenshot.

It is very important that you disable the JTAG interface, disable the internal clock devide by 8, enable clock output on PB1 and enable the correct clock source. The option to output the system clock on PB1 is required as the CPLD uses the clock internally e.g. for the DMA statemachine.

Programming the CPLDs

This project includes two CPLDs. To program both CPLDs you need to know that they are daisy-chained via their respective JTAG interfaces. The JTAG interface is as well available on the break-out port and is the 10-in IDC header. The CPLDs can be programmed in-circuit via the JTAG interface. The ATF1504 is Chip 1 and the ATF1508 is Chip 2. You can find the necessary chain file in the download section.

AVR Fuses

Unfortunately the program is a very old program no longer maintained and in Windows XP you cannot resize the sub-windows. So here just some words about the screenshot. First you see the main window which shows 2 chips. For each chip you need to set the JTAG instruction and the JEDEC file. Unfortunately the file name uses absolute paths, so in case you are using the chain file in the download section you need to adjust the files, by double-clicking on the filename.

You can of course create your own chain file, just select “New” in the “File” menu. Set the number of chips to 2 and select the appropriate device type and file. Make sure chip 1 is a ATF1504AS and chip 2 is a ATF1508AS. In case you want to program the chips individually you can just use the Bypass action of the chip you do not want to program.

Once you have setup everything hit the Run button. It takes quite some time until you see a reaction and output on the lower part of the window. Be patient.