From f5850892befc908f7deeae7b7d39f44e4f5ae293 Mon Sep 17 00:00:00 2001
From: Jan Breuer <jan.breuer@jaybee.cz>
Date: 周五, 16 11月 2012 19:57:45 +0800
Subject: [PATCH] Initial implementation of SCPI parser library
---
README.md | 73 +++++++++++++++++++++++++++++++++++-
1 files changed, 71 insertions(+), 2 deletions(-)
diff --git a/README.md b/README.md
index 442b9f7..5ba4e34 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,73 @@
-scpi-parser
+SCPI parser library
===========
-SCPI parser library
\ No newline at end of file
+[SCPI](http://en.wikipedia.org/wiki/Standard_Commands_for_Programmable_Instruments) Parser library aims to provide parsing ability of SCPI commands on instrument side. All commands are defined by its patterns eg: "STATus:QUEStionable:EVENt?".
+
+Source codes are devided into few files to provide better portability to other systems.
+
+- *scpi.c* - provides the core parser library
+- *scpi_error.c* - provides basic error handling (error queue of the instrument)
+- *scpi_ieee488.c* - provides basic implementation of IEEE488.2 mandatory commands
+- *scpi_minimal.c* - provides basic implementation of SCPI mandatory commands
+- *scpi_utils.c* - provides string handling routines and conversion routines
+
+- *test-parser.c* - is the basic non-interactive demo of the parser
+
+Implementation to your instrument
+-------------
+First of all you need to fill structure of SCPI command definitions
+
+ scpi_command_t scpi_commands[] = {
+ { .pattern = "*IDN?", .callback = SCPI_CoreIdnQ,},
+ { .pattern = "*RST", .callback = SCPI_CoreRst,},
+ SCPI_CMD_LIST_END
+ };
+
+Than you need to initialize interface callbacks structure. If you don't want to provide some callbacks, just initialize it as NULL. write callback is mandatory and is used to output data from the library.
+
+ scpi_interface_t scpi_interface = {
+ .write = myWrite,
+ .error = NULL,
+ .reset = NULL,
+ .test = NULL,
+ };
+
+Important thing is command buffer. Maximum size is up to you and it should be larger than any possible largest command.
+
+ #define SCPI_BUFFER_LENGTH 256
+ char myBuffer[SCPI_BUFFER_LENGTH];
+
+ scpi_buffer_t scpi_buffer = {
+ .length = SCPI_BUFFER_LENGTH,
+ .data = myBuffer,
+ };
+
+The last structure is scpi context used in parser library.
+
+ scpi_context_t scpi_context;
+
+All these structures should be global variables of the c file or allocated by function like malloc. It is common mistake to create these structures inside a function as local variables of this function. This will not work. If you don't know why, you should read something about [function stack.](http://stackoverflow.com/questions/4824342/returning-a-local-variable-from-function-in-c).
+
+
+Now we are ready to connect everything together
+
+ SCPI_Init(&scpi_context, scpi_commands, &scpi_buffer, &scpi_interface);
+
+Test implementation of function myWrite, which outputs everything to stdout, can be
+
+ size_t myWrite(scpi_context_t * context, const char * data, size_t len) {
+ (void) context;
+ return fwrite(data, 1, len, stdout);
+ }
+
+Interactive demo can beimplemented using this loop
+
+ #define SMALL_BUFFER_LEN
+ char smbuffer[SMALL_BUFFER_LEN];
+ while(1) {
+ fgets(smbuffer, SMALL_BUFFER_LEN, stdin);
+ SCPI_Input(&scpi_context, smbuffer, strlen(smbuffer));
+ }
+
+
+
--
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