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build STM32 evaluation board for less than $20

ivan239955_stm1_st
Associate II
Posted on February 04, 2008 at 12:35

build STM32 evaluation board for less than $20

15 REPLIES 15
slawcus
Associate II
Posted on May 17, 2011 at 12:21

obtronix, have you seen

http://www.st.com/stonline/books/pdf/docs/6292.pdf

ST7 application note?

Processing power needed to control LCD in software is not problematic and with Cortex speed and very fast IRQs... you will not notice it. :) The problem is DC voltage on the LCD segment if something goes wrong in the software. Debuging and hence stopping SW control is not recommended.

obtronix
Associate II
Posted on May 17, 2011 at 12:21

thank I never saw that one, but I have look at simliar applicaton notes from other vendors.

my concern is not available throughput, but

''The problem is DC voltage on the LCD segment if something goes wrong in the software. Debuging and hence stopping SW control is not recommended. ''

that implies that you can never go into standby mode, so average current consumption will be high, whereas micro's with built in LCD controllers can run the LCD using 20 or so uA.

adrian3
Associate II
Posted on May 17, 2011 at 12:21

Quote:

I see that board is creating some interest :) This is an early prototype

where STM32 is driving 128 Segment (Quadruplex drive) Glass through GPIOs

STOne-32

Any more details on this, as it looks as if I may be doing something similar next.

slawcus
Associate II
Posted on May 17, 2011 at 12:21

So... STM32 designers, I have a new assignment for you. STM32 with integrated 160 segment LCD controler.

obtronix
Associate II
Posted on May 17, 2011 at 12:21

''obtronix, have you seen this ST7 application note? ''

I was thinking maybe you can use the STM32 internal pull-up/pull-down resistors instead of external resistors to drive the LCD three voltage levels, but you can't turn both of them on at the same time (as far as I can see),.... but short two pins together and enable pull up on one and pull down on the other, that should give you VCC/2, getting GND and VCC from the two shorted pins is easy too

hmm I'm sure I not thinking of something

[ This message was edited by: obtronix on 27-01-2008 00:50 ]

ivan239955_stm1_st
Associate II
Posted on May 17, 2011 at 12:21

- WIGGLER JTAG schematic is available on many websites. For example see attached picture.

- JTAG is not mandatory for STM32 flash programing. UART flash bootloader works happily without JTAG - just set proper levels at boot0,1 pins, attach UART1 to PC