microSD Mass Storage for Blockheads and Fatties
Intro
Raw blocks or filesystem? A real filesystem is hefty and several times larger than the Forth kernel itself. But if you really want to exchange data with other systems you need some sort of compatible storage medium like a microSD with a FAT filesystem. For a standalone Forth system, especially a embedded system, a block storage (on internal Flash or external Media) or no mass storage at all fill the bill.
Hardware
You can build a very cheap microSD adapter by yourself with a microSD to SD adapter. You have to solder only 7 wires to a pin header. The breakout board for microSD cards from Adafruit have a level shifter, but this is not needed because the levels on the Nucleo are already 3.3 V. Only the CD pin is missing, this could be handy to detect a microSD card.  |
 |
| SD pin | microSD pin | Name | Description | Arduino/Nucleo Pin |
|---|---|---|---|---|
| 1 | 2 | nCS | Card Select [CS] | D10 |
| 2 | 3 | DI | Serial Data In [MOSI] | D11 |
| 3 | - | VSS | Ground | GND |
| 4 | 4 | VDD | Power 3.3 V | 3V3 |
| 5 | 5 | CLK | Serial Clock [SCLK] | D13 |
| 6 | 6 | VSS | Ground | GND |
| 7 | 7 | DO | Serial Data Out [MISO] | D12 |
| 8 | 8 | NC | Unused | |
| 9 | 1 | NC | Unused |
Block size 512 Bytes, SPI mode 0 (CPHA=0, CPOL=0), Pull-up on MISO.
Raw Blocks
One Forth block consists of two microSD sectors. No filesystem is involved, blocks are mapped direct to the sectors: block_number = sector_number / 2. Caution! If you write a block on a formatted disk you will destroy the filesystem. Block 0 for example is the Master Boot Sector, to overwrite this sector/block would end in a disaster. If you really want to share blocks and filesystem on the same disk you have to create an additional partition for the Forth blocks. Or if you only want to play with some toy blocks, you can abuse the boot loader, because it is usually not required and you can therefore use blocks from 10 to 100. But be warned, do not do this on the SD card with the vacation pictures!Block (Virtual Memory) Words
block ( n -- a ) Return address of buffer for block n. 0 on error. buffer ( n -- a ) Return address of buffer for block n. Does not get the block from disk. 0 on error. empty-buffers ( -- ) Marks all block buffers as empty. update ( -- ) Marks most recent block as updated (dirty). save-buffers ( -- ) Transfers the contents of each updated block buffer to disk. flush ( -- ) save-buffers empty-buffers list ( n -- ) Display block n. The block is displayed as 16 numbered lines, each of 64 characters. load ( n -- ) Interprets the content of block n. sdinit ( -- ) Initializes the sd, sets the block count. sdblocks ( -- n ) Gets the block count.
Block Editor
VI or EMACS keybindings? VI has a line editing mode too, fine for really dumb terminals.- VIBE https://www.complang.tuwien.ac.at/forth/vibe-2.1ans.fs http://kestrelcomputer.github.io/kestrel/2016/03/29/vibe-2.2
- Standard Mecrisp block editor
Raw Blocks and GNU/Linux
Example 2 GiB microSD FAT16 formatted, show the disk parameter with fdisk:# fdisk /dev/sdf ... Befehl (m für Hilfe): p Festplatte /dev/sdf: 1,91 GiB, 2032664576 Bytes, 3970048 Sektoren Festplattenmodell: FCR-HS219/1 Einheiten: Sektoren von 1 * 512 = 512 Bytes Sektorgröße (logisch/physikalisch): 512 Bytes / 512 Bytes E/A-Größe (minimal/optimal): 512 Bytes / 512 Bytes Festplattenbezeichnungstyp: dos Festplattenbezeichner: 0x00000000 Gerät Boot Anfang Ende Sektoren Größe Kn Typ /dev/sdf1 249 3967487 3967239 1,9G 6 FAT16Fill the SD with zeros (1'000'000 sectors à 512 Bytes), that takes about 5 Minutes:
# dd if=/dev/zero of=/dev/sdf count=1000000 1000000+0 Datensätze ein 1000000+0 Datensätze aus 512000000 Bytes (512 MB, 488 MiB) kopiert, 271,43 s, 1,9 MB/sWrite the first block with the famous F example letter-f.block from Starting Forth
, Leo Brodie:
# dd if=letter-f.block of=/dev/sdf 2+0 Datensätze ein 2+0 Datensätze aus 1024 Bytes (1,0 kB, 1,0 KiB) kopiert, 0,00226272 s, 453 kB/sPut the microSD card into the SD adapter and startup the Mecrisp-Cube Nucleo:
Mecrisp-Cube 1.2.0 for STM32WB55 (C) peter@spyr.ch.
Based on Mecrisp-Stellaris 2.5.2 by Matthias Koch.
0 list
Block# 0
0 \ Large letter F
1 : STAR [CHAR] * EMIT ;
2 : STARS 0 DO STAR LOOP ;
3 : MARGIN CR 30 SPACES ;
4 : BLIP MARGIN STAR ;
5 : BAR MARGIN 5 STARS ;
6 : F BAR BLIP BAR BLIP BLIP CR ;
7
8 F
9
10
11
12
13
14
15
ok.
0 load
*****
*
*****
*
*
ok.
ok.
0 block hex. 200216F8 ok.
0 block 1200 dump
200216F0 : 00 01 00 00 D9 86 03 00 5C 20 4C 61 72 67 65 20 | ........ \ Large |
20021700 : 6C 65 74 74 65 72 20 46 20 20 20 20 20 20 20 20 | letter F |
20021710 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021720 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021730 : 20 20 20 20 20 20 20 20 3A 20 53 54 41 52 20 20 | : STAR |
20021740 : 20 20 5B 43 48 41 52 5D 20 2A 20 45 4D 49 54 20 | [CHAR] * EMIT |
20021750 : 3B 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | ; |
20021760 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021770 : 20 20 20 20 20 20 20 20 3A 20 53 54 41 52 53 20 | : STARS |
20021780 : 20 20 30 20 44 4F 20 20 53 54 41 52 20 20 4C 4F | 0 DO STAR LO |
20021790 : 4F 50 20 3B 20 20 20 20 20 20 20 20 20 20 20 20 | OP ; |
200217A0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200217B0 : 20 20 20 20 20 20 20 20 3A 20 4D 41 52 47 49 4E | : MARGIN |
200217C0 : 20 20 43 52 20 33 30 20 53 50 41 43 45 53 20 3B | CR 30 SPACES ; |
200217D0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200217E0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200217F0 : 20 20 20 20 20 20 20 20 3A 20 42 4C 49 50 20 20 | : BLIP |
20021800 : 20 20 4D 41 52 47 49 4E 20 53 54 41 52 20 3B 20 | MARGIN STAR ; |
20021810 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021820 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021830 : 20 20 20 20 20 20 20 20 3A 20 42 41 52 20 20 20 | : BAR |
20021840 : 20 20 4D 41 52 47 49 4E 20 35 20 53 54 41 52 53 | MARGIN 5 STARS |
20021850 : 20 3B 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | ; |
20021860 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021870 : 20 20 20 20 20 20 20 20 3A 20 46 20 20 20 20 20 | : F |
20021880 : 20 20 42 41 52 20 42 4C 49 50 20 42 41 52 20 42 | BAR BL IP BAR B |
20021890 : 4C 49 50 20 42 4C 49 50 20 43 52 20 3B 20 20 20 | LIP BLIP CR ; |
200218A0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200218B0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200218C0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200218D0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200218E0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200218F0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021900 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021910 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021920 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021930 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021940 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021950 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021960 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021970 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021980 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021990 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200219A0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200219B0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200219C0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200219D0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200219E0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
200219F0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A00 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A10 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A20 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A30 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A40 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A50 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A60 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A70 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A80 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021A90 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021AA0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021AB0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021AC0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021AD0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021AE0 : 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
20021AF0 : 20 20 20 20 20 20 20 20 00 00 00 00 01 00 00 00 | ........ |
20021B00 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B10 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B20 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B30 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B40 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B50 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B60 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B70 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B80 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021B90 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021BA0 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
20021BB0 : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ........ ........ |
ok.
FAT Filesystem
FAT is the de-facto standard for embedded systems and mobile devices. Based on FatFs - Generic FAT Filesystem Module. It supports FAT (12, 16, and 32) and exFAT formatted SD cards.
Forth source files
include filename ( -- ) Interprets the content of the file. included ( a u -- ) Interprets the content of the file.
Filesystem API
The C function prototype forf_open looks like this:
FRESULT f_open ( FIL* fp, /* [OUT] Pointer to the file object structure */ const TCHAR* path, /* [IN] File name */ BYTE mode /* [IN] Mode flags */ );The parameter order for the Forth Word is the same: a1 is address of the file object structure, a2 is the address of the filename array (0 terminated string).
f_open ( a1 a2 w -- u ) opens a file.
typedef struct {
FFOBJID obj; /* Object identifier */
BYTE flag; /* File object status flags */
BYTE err; /* Abort flag (error code) */
FSIZE_t fptr; /* File read/write pointer (Byte offset origin from top of the file) */
DWORD clust; /* Current cluster of fptr (One cluster behind if fptr is on the cluster boundary. Invalid if fptr == 0.) */
LBA_t sect; /* Current data sector (Can be invalid if fptr is on the cluster boundary.)*/
#if !FF_FS_READONLY
LBA_t dir_sect; /* Sector number containing the directory entry */
BYTE* dir_ptr; /* Ponter to the directory entry in the window */
#endif
#if FF_USE_FASTSEEK
DWORD* cltbl; /* Pointer to the cluster link map table (Nulled on file open. Set by application.) */
#endif
#if !FF_FS_TINY
BYTE buf[FF_MAX_SS]; /* File private data transfer buffer (Always valid if fptr is not on the sector boundary but can be invalid if fptr is on the sector boundary.) */
#endif
} FIL;
FIL name ( -- a ) creates a file objectSee also f_open
File Access
- f_open - Open/Create a file
- f_close - Close an open file
- f_read - Read data from the file
- f_write - Write data to the file
- f_lseek - Move read/write pointer, Expand size
- f_truncate - Truncate file size
- f_sync - Flush cached data
- f_forward - Forward data to the stream
- f_expand - Allocate a contiguous block to the file
- f_gets - Read a string
- f_putc - Write a character
- f_puts - Write a string
- f_printf - Write a formatted string
- f_tell - Get current read/write pointer
- f_eof - Test for end-of-file
- f_size - Get size
- f_error - Test for an error
Directory Access
- f_opendir - Open a directory
- f_closedir - Close an open directory
- f_readdir - Read a directory item
- f_findfirst - Open a directory and read the first item matched
- f_findnext - Read a next item matched
File and Directory Management
- f_stat - Check existance of a file or sub-directory
- f_unlink - Remove a file or sub-directory
- f_rename - Rename/Move a file or sub-directory
- f_chmod - Change attribute of a file or sub-directory
- f_utime - Change timestamp of a file or sub-directory
- f_mkdir - Create a sub-directory
- f_chdir - Change current directory
- f_chdrive - Change current drive
- f_getcwd - Retrieve the current directory and drive
Volume Management and System Configuration
- f_mount - Register/Unregister the work area of the volume
- f_mkfs - Create an FAT volume on the logical drive
- f_fdisk - Create partitions on the physical drive
- f_getfree - Get free space on the volume
- f_getlabel - Get volume label
- f_setlabel - Set volume label
- f_setcp - Set active code page
Peter Schmid - 2020-06-03
Comments
| I | Attachment | History | Action | Size | Date | Who | Comment |
|---|---|---|---|---|---|---|---|
 gif |
MMC-SD-miniSD-microSD-Color-Numbers-Names.gif | r1 | manage | 19.7 K | 2020-06-03 - 07:39 | PeterSchmid | |
 block |
letter-f.block | r1 | manage | 1.0 K | 2020-06-12 - 19:46 | PeterSchmid | |
 jpg |
nucleo-sd-adapter.jpg | r1 | manage | 347.2 K | 2020-06-14 - 14:52 | PeterSchmid |
Topic revision: r16 - 2020-06-30 - PeterSchmid
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