- #1
Jdo300
- 554
- 5
Hello All,
I am currently trying to figure out how to program the AD9959 IC using a serial connection to my PC.
From reading through the datasheet for this chip, I learned that it uses the serial SPI interface to send and receive instructions and data. This chip has four channels of DDS and allows you to program the frequency (32-bit), phase-shift (14-bit), and amplitude (10-bit). The chip has a lot of other, more advanced features (like modulation and frequency sweeps) that I don't care to make use of.
My circuit board will also have some other digital inputs to control separate chips on the board that control the pulse width of the output signal (the DDS outputs sine waves but I will be using logic chips to convert them to short adjustable duty cycle square waves).
I'm just wondering how to use the serial port to select which chips I send data and instructions to. I *think* that I want to use the MAX3110E IC which can convert the RS232 level signals into the SPI compatible ones. The problem is that everything coming out of that chip is now serial and I'm not sure how to control where the bits go.
I was trying to come up with some kind of scheme where I could input the serial data into a shift register to control the lines of a multiplexer or something to route further bits to either the AD9959 or the chip that would control the pulse width.
As for the pulse width chip, I'm still looking into different ways to do it but I know I will want some kind of digital input to control it. To keep the complexity of the circuit down, I have decided to control all four channels with a single data input. I'm thinking I'll use either four or eight-bit input to control the duty cycle. Is there any simple method for routing the bits without using a microcontroller?
Thanks,
Jason O
I am currently trying to figure out how to program the AD9959 IC using a serial connection to my PC.
From reading through the datasheet for this chip, I learned that it uses the serial SPI interface to send and receive instructions and data. This chip has four channels of DDS and allows you to program the frequency (32-bit), phase-shift (14-bit), and amplitude (10-bit). The chip has a lot of other, more advanced features (like modulation and frequency sweeps) that I don't care to make use of.
My circuit board will also have some other digital inputs to control separate chips on the board that control the pulse width of the output signal (the DDS outputs sine waves but I will be using logic chips to convert them to short adjustable duty cycle square waves).
I'm just wondering how to use the serial port to select which chips I send data and instructions to. I *think* that I want to use the MAX3110E IC which can convert the RS232 level signals into the SPI compatible ones. The problem is that everything coming out of that chip is now serial and I'm not sure how to control where the bits go.
I was trying to come up with some kind of scheme where I could input the serial data into a shift register to control the lines of a multiplexer or something to route further bits to either the AD9959 or the chip that would control the pulse width.
As for the pulse width chip, I'm still looking into different ways to do it but I know I will want some kind of digital input to control it. To keep the complexity of the circuit down, I have decided to control all four channels with a single data input. I'm thinking I'll use either four or eight-bit input to control the duty cycle. Is there any simple method for routing the bits without using a microcontroller?
Thanks,
Jason O