[STM32GENERIC] FSMC - SRAM

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zmemw16
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Re: [STM32GENERIC] FSMC - SRAM

Post by zmemw16 » Tue Jun 13, 2017 9:54 am

you have a choice to make :)
http://www.stm32duino.com/viewtopic.php?f=3&t=2159
no, i've not seen a black vet/zet/zgt with sram fitted as yet
srp

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Pito
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Re: [STM32GENERIC] FSMC - SRAM

Post by Pito » Tue Jun 13, 2017 10:42 am

I have 2 questions:
1. so far I get strange results (see below), could this be a timing issue?
2. I ordered a "black" STM32F407ZET6 board, it has solder pads on the back side for SRAM. Did you find such a board with soldered SRAM?
1. what is your timing setting?
2. No, I got the black board 407ZET6 and soldered in the sram (256kx16, 10ns part), it works fine.
You have to solder 2x 100n 0603 smd ceramic capacitors and 10k resistor on the pads there as well..
Last edited by Pito on Tue Jun 13, 2017 11:30 am, edited 2 times in total.
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Zingg_JM
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Re: [STM32GENERIC] FSMC - SRAM

Post by Zingg_JM » Tue Jun 13, 2017 11:18 am

@Pito

Excellent, thank you, now it works!

I just changed to:

#define ADDSET 5
#define DATAST 5

I will look at the specs of my SRAM and the meaning (register bits) of these values later. Execution speed is not an issue for my e-paper.

Jean-Marc
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Pito
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Re: [STM32GENERIC] FSMC - SRAM

Post by Pito » Tue Jun 13, 2017 11:26 am

For 10ns Sram A=1, D=3 works fine here at 168MHz fcpu.
For 55ns Sram you have to experiment, I would start with A=15, D=15 and then go lower till problems occur.
You may use the Buble Sort demo in this thread for experiments.
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zmemw16
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Re: [STM32GENERIC] FSMC - SRAM

Post by zmemw16 » Tue Jun 13, 2017 12:07 pm

Pito wrote:
You have to solder 2x 100n 0603 smd ceramic capacitors and 10k resistor on the pads there as well..
i've the 100nf 0603's, please make my day and tell me a 10k 0805 will squeeze 0603 pads or even better that those pads are 0805 ;)
stephen

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Pito
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Re: [STM32GENERIC] FSMC - SRAM

Post by Pito » Tue Jun 13, 2017 1:34 pm

I've soldered 15k 0805 (it fits) there and it works fine.
15k.JPG
15k.JPG (25.13 KiB) Viewed 260 times
100n.JPG
100n.JPG (36.81 KiB) Viewed 257 times
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zmemw16
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Re: [STM32GENERIC] FSMC - SRAM

Post by zmemw16 » Tue Jun 13, 2017 3:29 pm

aarrrhhh memory is a fine thing, so is stubbing toe on sample books of smd r & c, lost in the stack.

you did make my day with the pictures though

stephen

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Pito
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Re: [STM32GENERIC] FSMC - SRAM

Post by Pito » Tue Jun 13, 2017 7:28 pm

This memory to solder is quite easy. You need a lot of solder flux to put onto the pins (first - do center the package at the pads and fix it by a tin blobs at the corners, do not care on shorts at this stage) and then simply run the iron tip (tinned) slowly over the pins from left to right, the tin finds the pads itself. The reminders of the tin (between the pins close to the package), if any, could be easily removed by desoldering copper wick wire (as the last step). The trick here is to use a LOT of flux, the package must swim in the sea of flux :)
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zmemw16
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Re: [STM32GENERIC] FSMC - SRAM

Post by zmemw16 » Tue Jun 13, 2017 8:03 pm

btw flux is a great solvent to galvanize solder paste into life and a good stir as well
does help to know the consistency of the original on receipt.

youtube on 'smd soldering tutorials' has this guy, i'm already subscribed :)
quite a few about drag soldering
https://www.youtube.com/user/jkgamm041/ ... ity_view=3

stephen

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Pito
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Re: [STM32GENERIC] FSMC - SRAM

Post by Pito » Wed Jul 05, 2017 1:32 pm

@daniel:
Would it be possible to make the

Code: Select all

void SystemInit_ExtMemCtl(void)

weak such we can define our version in variant.c ?
In my naive attempt I put it into but it did not take over.
Or maybe a hint how to.
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