PIC32 - Revision history

Adminguy: /* DMA */

2019-11-05T07:23:17Z

DMA

2019-11-01T21:57:05Z

2019-11-01T02:00:35Z

2019-10-29T21:26:30Z

Atomic Operations on bits

2019-10-29T21:25:31Z

Cache can stop initialization of large variables when using them for DMA

2019-10-29T21:25:04Z

Cache can stop initialization of large variables when using them for DMA

2019-10-29T21:23:39Z

Prefetch Cache (MZ)

2019-10-29T21:23:21Z

2019-10-29T21:22:38Z

Tips

2019-10-28T02:49:52Z

@@ Line 39: / Line 39: @@
 ====Not all Pic32 have 16 bits of DMA memory====
 Earlier pics (PIC32MX440) only have 8 bits in DCHxSSIZ or DSIZ. If it only outputs 256 bytes, this is why. Check that register, because it's not mentioned anywhere else.
 ===Prefetch Cache (MZ)===
 ====Cache can stop initialization of large variables when using them for DMA====

← Older revision		Revision as of 21:57, 1 November 2019
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	Reference: http://web.archive.org/web/https://www.microchip.com/forums/m1116587.aspx		Reference: http://web.archive.org/web/https://www.microchip.com/forums/m1116587.aspx
		+
		+	==Code==
		+	[[PIC32_Examples]] - scraps atm

	==Resources==		==Resources==

@@ Line 1: / Line 1: @@
 Some things I've learned about PIC32MX and MZ.
 ==Tips==
-===MX is not MZ===
+===MX is not MZ is not C is not MM===
-Essentially there are two distinct PIC32 architectures. MX and MZ (let's forget about MM). The reference manuals (Family Reference Manuals) that apply to MZ do not apply to MX. A simple thing to misunderstand for beginners. Use the reference manual that is mentioned in your Pic's particular datasheet.
+For starters, there are two distinct PIC32 architectures. MX and MZ (let's forget about the rest). The reference manuals (Family Reference Manuals) that apply to MZ do not apply to MX. A simple thing to misunderstand for beginners. Use the reference manual that is mentioned in your Pic's particular datasheet.
 ===PIC32 can be Power Hungry===

@@ Line 20: / Line 20: @@
 ===Atomic Operations on bits===
 See:
-  IFS4bits.DMA1IF = 0 //slow, can cause problems
+  IFS4bits.DMA1IF = 0 //takes a few cycles, can cause problems
-  IFS4CLR = _IFS4_DMA1IF_MASK //immediate. better.
+  IFS4CLR = _IFS4_DMA1IF_MASK //takes one cycle. better.
 ===Resets===

@@ Line 44: / Line 44: @@
+  }
 If you have cache enabled (it's enabled by default on MZ) you will only get 6000 or so of the variables changed for DMA. If you go to debugging - watch - choose array[x] and export to csv, you will see all the values have 0xFF but the dma will output about 6000 of 0xFF and then 4000 of 0's or 1's. The solution is to disable the cache via http://web.archive.org/web/https;//microchipdeveloper.com/32bit:mz-cache-disable
 Reference: http://web.archive.org/web/https://www.microchip.com/forums/m1116587.aspx

@@ Line 41: / Line 41: @@
 Let's say you have a loop
   for(x=0,x<10000,x++){
- array[x] = 0xFF;
+     array[x] = 0xFF;
+  }
 If you have cache enabled (it's enabled by default on MZ) you will only get 6000 or so of the variables changed for DMA. If you go to debugging - watch - choose array[x] and export to csv, you will see all the values have 0xFF but the dma will output about 6000 of 0xFF and then 4000 of 0's or 1's. The solution is to disable the cache via http://web.archive.org/web/https;//microchipdeveloper.com/32bit:mz-cache-disable

@@ Line 35: / Line 35: @@
 ====DMA - If you CFORCE, and it finishes, you must CHEN again to CFORCE again====
 Subject.
 ==Resources==
 ===Family Reference Manuals===

← Older revision		Revision as of 02:49, 28 October 2019
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	There are a number of well commented (unlike most garbage online) examples that are ideal for someone learning about setup of pic32 peripherals in the Peripheral Libraries Examples. Link: https://people.ece.cornell.edu/land/courses/ece4760/PIC32/PLIB_examples/plib_examples/		There are a number of well commented (unlike most garbage online) examples that are ideal for someone learning about setup of pic32 peripherals in the Peripheral Libraries Examples. Link: https://people.ece.cornell.edu/land/courses/ece4760/PIC32/PLIB_examples/plib_examples/
	===Books===		===Books===
		+
		+	{{Electronics}}