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Forum Index : Microcontroller and PC projects : Useful port expander chip: HV5530

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matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10570

Posted: 08:28am 12 Apr 2018

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I've come to that time of life where I need to build a Nixie clock (it comes to everyone eventually but no-one knows why). The design is in this thread but I thought it worth bringing to more general attention the driver chip I'm using.
The HV5530 is a 32-bit SPI to parallel converter with open collector outputs capable of switching up to 300V. It can be seen in the picture in the PLCC adapter behind the Nixie tube. There is one small downside in that it uses 12v logic so I am using one of the cheap level converters between the Micromite and the HV5530. The simple program below shows how easy it is to drive
Set up SPI for 32-bit output, send the data, then pulse the latch pin high. The BL pin enables and disables the output and can be used with a PWM signal for brightness control. The module to the left of the picture is converting 12VDC to 180VDC to connect to the Nixie tube anode via a 22K resistor to give a 2mA drive current.

Quote Option explicit
option default NONE
const BL = 26
const LATCH = 24
setpin BL,dout
setpin LATCH,dout
PIN(BL)=0
PIN(LATCH)=0
spi open 1000000,1,32
spi write 1,&H0
pulse LATCH,0.01
PIN(BL)=1
do
spi write 1,512 '0
pulse LATCH,0.01
pause 1000
spi write 1,1 '1
pulse LATCH,0.01
pause 1000
spi write 1,2 '2
pulse LATCH,0.01
pause 1000
spi write 1,4 '3
pulse LATCH,0.01
pause 1000
spi write 1,8 '4
pulse LATCH,0.01
pause 1000
spi write 1,16 '5
pulse LATCH,0.01
pause 1000
spi write 1,32 '6
pulse LATCH,0.01
pause 1000
spi write 1,64 '7
pulse LATCH,0.01
pause 1000
spi write 1,128 '8
pulse LATCH,0.01
pause 1000
spi write 1,256 '9
pulse LATCH,0.01
pause 1000
loop
end

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