Electronics
Dual 8 bits DAC - SPI - MAX549
- Details
- Category: SPI boards
- Hits: 1573
Fig. 1 Dual 8bits SPI DAC
Description:
This board is a dual 8bits DAC with an SPI interface. It is based around 2 Maxim chip: a dual 8 bits digital-to-analog converter MAX549A, and a voltage reference MAX61xx.
It connects to a host with an SPI bus, up to 10 MHz.
The voltage reference can be choosen between MAX6125, 6141 or 6145 for a voltage reference (and maximum output voltage) of 2.5, 4.096 or 4.5 V respectively.
The board can be powered from 2.5 to 5V. But the voltage reference dictates the lower power supply. The power supply needs to be at least 200mv higher than the voltage reference.
Schematic:
The schematic is as simple as it can get. U2 provides voltage reference to the DAC chip U1.
U2 can be selected from the MAX 61xx chips listed above. The thing to remember is that the power supply needs to be at least 200mV higher than the desired reference voltage.
Specifications:
Input voltage 2.5 to 5V
InterfaceSPI 10MHz
CS selectable by jumper
Output voltage0 to Vref
8 bits resolution
Voltage referencedefined by chip MAX61xx
Initially, a MAX6141 was selected for it, in an SO08 package, simply because I had one in my drawer. The board is powered with a 5V processor board. It provides an output from 0 to 4.096 V
The CS signal is pulled high by default with R1. U1 is active with CS low, so it keeps U1 inactive by default. JP1 allows to select which CS line from the SPI interface is used.
The SPI interface is common across the SPI boards, and provides the following signals: SCK, MISO, MOSI, 3 chip select signals and power supply.
The outputs are on JP3 and JP4, also common across analog boards.
Fig. 2 Dual 8 bits SPI DAC schematic
Construction:
The PCB fits on a small single sided board. The PCB is designed to fit on one of the typical size for the board designed here. All components are on the top side except for U2, the voltage reference, which is on the bottom side (copper side).
Fig. 3a Dual 8 bits DAC SPI layout
Start with the lowest components, and continue with the higher ones on the top side. I put component in sockets when possible, so I usually test the board without them first, making sure the voltage is as expected... Only then are they put into their socket. Keep the MAX549 out for now.
The connectors JP2, JP3 and JP4 are optional. You can either solder cables directly on the board, or use connector to connect various boards together.
Once all the components are soldered on the top side, solder U2 on the copper side.
Fig. 3b Bottom side with U2
Before fitting the DAC in its socket, you can test the board as described below.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| Dual 8bits SPI DAC Component list |
|---|
| C1: 100 nF C2: 2.2 nF R1: 100 K U1: MAX549A U2: MAX6125, 6141 or 6145 JP5: jumper 3x2 JP2: Connector AMP MT 8 pins male (optional) JP3, JP4: Connector AMP MT 3 pins male (optional) |
How to use / Testing:
To check the board, connect the board to an SPI interface. Leave jumper off JP5 for now. Power up the board.
Check you have the Vcc supply on pin 8 of U1 socket and the reference volateg on pin 7.
With U1 in its socket, the output voltage will be 0V after power up.
To check the DAC is working, you need a processor board running the SPI DAC tutorial. Just make sure you set the switch on JP1 to the proper CS line.
Files and links:
Eagle PCB and schematics files for Dual 8 bits SPI DAC.PDFs of PCB, layout and schematics of Dual 8 bits SPI DAC.
PIC Tutorials for Dual 8 bits SPI DAC.
Maxim MAX549A.
Maxim MAX6125, MAX6141, MAX6145.
Microwire Eeprom - SPI - 93C46
- Details
- Category: SPI boards
- Hits: 1987
Fig. 1 Microwire Eeprom 93C46
Description:
This board is a Microwire Eeprom, with an SPI interface. It is based around a Microwire serial EEPROM, like 93C06 or 93C46.
It connects to a host with an SPI bus, up to 1 MHz.
The memory available depends on the chip used. It is 1024 bits, organised as 64 words of 16 bits on a 93C46.
The interface is Microwire, which is close to SPI, and can be implemented with the SPI interface of the tutorials. The main difference is that the clock is limited to 1 MHz, CS is active high, and the communication is not on a multiple of 8 bits.
The board can be powered from 2.7 to 5V.
Schematic:
Specifications:
Input voltage 2.7 to 5V
Interface Microwire 1MHz
CS selectable by jumper
MemoryDepends on chip
1K with 93C46
The schematic is straight forward. U1 is connected to the SPI interface with its various signals (MISO, MOSI, SCK, CS) on K1. Jumper J1 allows to select between CS0, CS1 or CS2 from the SPI interface to drive the chip. CS is active high, so R1 pulls it low by default.
U1 can be selected from the various Microwire eerom family 93Cx6: 93C06, 93C46, 93C56...
R2 is here to have an easy Gnd point to connect a test instrument.
Fig. 2 Microwire Eeprom schematic
Construction:
The PCB fits on a small single sided board. All components are on the top side.
Fig. 3 Microwire Eeprom layout
Start with the lowest components, and continue with the higher ones on the top side.
R2 is made up of a piece of resistor's lead. It's here to easily attach a clip from a test instrument or have a Gnd test point.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| Microwire Eeprom Component list |
|---|
| C1: 100 nF R1: 100 K R2: resistor's lead U1: 93Cx6 memory chip (93C46) + 8 pins DIL socket J1: jumper 3x2 K1: Connector AMP MT 8 pins male |
How to use / Testing:
To check the board, connect the board to an SPI interface. Leave jumper off J1 for now. Power up the board.
Check you have the Vcc supply between pin 5 and 8 of U1 socket.
To check the Eeprom is working, you need a processor board running the Microwire Eeprom tutorial. Just make sure you set the switch on J1 to the proper CS line.
Files and links:
Eagle PCB and schematics files for Microwire Eeprom.PDFs of PCB, layout and schematics of Microwire Eeprom.
PIC Tutorials for Microwire Eeprom.
Microwire 93C46.
16 bits ADC - SPI - MAX1162
- Details
- Category: SPI boards
- Hits: 659
Fig. 1 16 bits SPI ADC
Description:
This board is a 16 bits ADC with an SPI interface. It is based around 2 Maxim chip: the 16 bits analog-to-digital converter MAX1162, and a voltage reference MAX60xx. A different voltage reference chip was selected for this board than for the DAC SPI board, because of increased resolution. The MAX60xx voltage reference have a precision of 0.2%, whereas the MAX61xx voltage reference is about 1%. The DAC has a resolution of 8 bits, against 16 bits for this ADC.
It connects to a host with an SPI bus, up to 10 MHz.
The voltage reference can be choosen between MAX6012, 6021, 6025, 6030, 6041 or 6045 for a voltage reference (and maximum input voltage) of 1.247, 2.048, 2.5, 3, 4.096 or 4.5 V respectively.
The board can be powered from 4.5 to 5V. This is limited by the analog sectoin of the converter.
Schematic:
The schematic is as simple as it can get. R1/C1 filter the power supply to the analog section of the chip. C2 filters the digital section.
IC2 , a high precision chip, provides voltage reference to the ADC chip IC1.
IC2 can be selected from the MAX 60xx chips listed above. It determines the range and resolution of the board.
Specifications:
Input voltage 4.5 to 5V
InterfaceSPI 10MHz
CS selectable by jumper
Iutput voltage0 to Vref
16 bits resolution
Voltage referencedefined by chip MAX60xx
The MAX6041 was selected for it, simply because I had one in my drawer. It gives a voltage reference of 4.096 V, which over 16 bits gives a resolution of 62.5 uV. (62.5uV * 2^16 = 4.096V)
The board is powered with a 5V processor board.
The CS signal is pulled high by default with R2. U1 is active with CS low, so it keeps IC1 inactive by default. JP2 allows to select which CS line from the SPI interface is used.
The SPI interface is common across the SPI boards, and provides the following signals: SCK, MISO, MOSI, 3 chip select signals and power supply.
The input is on JP3, also common across analog boards.
Fig. 2 16 bits SPI ADC schematic
Construction:
The PCB fits on a small single sided board. The PCB is designed to fit on one of the typical size for the board designed here. All components are on the top side.
Fig. 3 16 bits ADC SPI layout
Start with the lowest components, IC1 and IC2, and continue with the higher ones. (On the top photo, this is a beta board, where the SPI connector is on the wrong side. This is corrected in the PDF or eagle file.
The connectors JP1 and JP3 are optional. You can either solder cables directly on the board, or use connector to connect various boards together.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| 16 bits SPI ADC Component list |
|---|
| C1, C2, C4: 100 nF smd 1206 C3: 10 nF smd 1206 R1: 10 R2: 47k smd 1206 or 0603 IC1: MAX1162 U2: MAX6012, 6021, 6025, 6030, 6041 or 6045 JP2: jumper 3x2 JP1: Connector AMP MT 8 pins male (optional) JP3: Connector AMP MT 3 pins male (optional) |
How to use / Testing:
To check the board, connect the board to an SPI interface. Leave jumper off JP2 for now. Power up the board.
Check you have the Vcc supply on IC1 and the reference voltage.
To check the ADC is working, you need a processor board running the SPI ADC tutorial. Just make sure you set the switch on JP2 to the proper CS line.
Files and links:
Eagle PCB and schematics files for 16 bits SPI ADC.PDFs of PCB, layout and schematics of 16 bits SPI ADC.
Maxim MAX1162.
Maxim MAX6012, MAX6041, MAX6045.
Radio tranceiver - SPI - RF12
- Details
- Category: SPI boards
- Hits: 2478
Fig. 1 RFM12 Radio tranceiver
Description:
This board is a radio transceiver based around the RFM12 module from HopeRF. It is a cheap and relatively easy to use module, with good range for most low datarate radio/wireless applications.
It connects to a host with an SPI bus, up to 10 MHz.
The board can be powered from 2.5 to 5V.
Schematic:
The schematic is as simple as it can get. C1 filters the power supplies, and R2 pulls FSK high so the board can be managed completely through the SPI bus.
The CS signal is selected with JP1, the IRQ signal, when needed is selected with JP2. This signal goes down low when a event generating an interrupt in the module occurs.
The SPI interface is common across the SPI boards, and provides the following signals: SCK, MISO, MOSI, 3 chip select signals and power supply.
Specifications:
Input voltage 2.5 to 5V
InterfaceSPI 10MHz
CS selectable by jumper
Frequency433, 868 or 915 MHz
Rangeup to 300m, depends on antenna
Data rateup to 112.5 Kbps
Fig. 2 Radio tranceiver schematic
Construction:
The PCB fits on a small single sided board. All components are on the top side.
Fig. 3 Radio tranceiver layout
Start with the 2 wire links between JP1 and JP2. Continue with the smd components R1, R2, C1 and LED1. You can leave JP1 and JP2 out, and solder the tracks to link the CS and IRQ lines. Then K1 and finally the RFM12 module.
The antenna can be either the onboard one, or a piece of wire. Make sure you solder the proper track beside PAD5. The lenght of the wire antenna depends of the base band of the module:
- 433MHz: 164.7mm
- 868MHz: 82.2mm
- 915MHz: 77.9mm
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| Radio tranceiver Component list |
|---|
| C1: 1 uF smd R1: 390 smd R2: 10 K smd U1: RFM12 transceiver module LED1: red LED smd JP1, JP2: jumper 3x2 K1: Connector AMP MT 8 pins male |
How to use / Testing:
To check the board, you'll need a pair of them, and run the SPI Radio transceiver tutorial. Just make sure you set the switch on JP1 to the proper CS line.
Files and links:
Eagle PCB and schematics files for Radio tranceiver.PDFs of PCB, layout and schematics of Radio tranceiver.
PIC Tutorials for RFM12 Radio tranceiver.
RF12 C library for CCS compiler, compatible with Microchip MiMac.
RFM12 FSK Radio tranceiver.