accessing array's row 0

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Read-Only Author Bahri Okuroglu Posted 23-Oct-2001 08:35 GMT Toolset C51	accessing array's row 0 Bahri Okuroglu I have a matrix for the keyboard layout in my program as follows: code unsigned char buttons[BUTTON_COUNT][KEY_TABLE_WIDTH] = { {'8', 'u', 'ü', 'v', EMPTY_CODE}, {'7', 'r', 's', 'ş', 't'}, {'6', 'ö', 'p', 'q', EMPTY_CODE}, {'5', 'l', 'm', 'n', 'o'}, {'1', 'a', 'b', 'c', 'ç'}, {'2', 'd', 'e', 'f', EMPTY_CODE}, {'3', 'g', 'ğ', 'h', 'ı'}, {'4', 'i', 'j', 'k', EMPTY_CODE}, {'9', 'w', 'x', 'y', 'z'}, {'0', ' ', ':', '-', EMPTY_CODE}, {RIGHT_ARROW,EMPTY_CODE, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE}, {LEFT_ARROW, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE}, {ESC, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE}, {DEL, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE}, {CAPS, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE}, {ENTER, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE, EMPTY_CODE} }; I use this table to use keyboard as in gsm phones to produce letters using 10 buttons. Code works fine, but when I push on the button 0, it fails to access the row 0 of the array. I can get key '7', but cannot get key '8'. It finds 0x00 for the first row members. I studied the code produced and tried to investigate using debugger; but they all seem OK to me. However, when I program the AT89C55WD with this code, it cannot find the keys (8, ...) for button 0. Please note all the other keys are OK. I could not solve this problem, and inserted a dummy row to the table at row 0, and indexed the table with not the button pressed, but with (button+1). This worked, but since it is just a work-around; I really wonder the reason. Any ideas?

Read-Only Author Andrew Neil Posted 23-Oct-2001 10:53 GMT Toolset C51	RE: accessing array's row 0 Andrew Neil As a test, I tried this: #define EMPTY_CODE 'Z' #define RIGHT_ARROW 'R' #define LEFT_ARROW 'L' #define ESC 'E' #define DEL 'D' #define CAPS 'C' #define ENTER 'E' #define BUTTON_COUNT 16 #define KEY_TABLE_WIDTH 5 void list_buttons( void ) { unsigned char row; unsigned char col; for( row = 0; row < BUTTON_COUNT; ++row ) { for( col = 0; col < KEY_TABLE_WIDTH; ++col ) { printf( "buttons[%2d][%2d] = '%c'\n", (unsigned int)row, (unsigned int)col, buttons[row][col] ); } printf( "\n" ); } } and got this: buttons[ 0][ 0] = '8' buttons[ 0][ 1] = 'u' buttons[ 0][ 2] = 'ü' buttons[ 0][ 3] = 'v' buttons[ 0][ 4] = 'Z' buttons[ 1][ 0] = '7' buttons[ 1][ 1] = 'r' buttons[ 1][ 2] = 's' buttons[ 1][ 3] = 's' buttons[ 1][ 4] = 't' buttons[ 2][ 0] = '6' buttons[ 2][ 1] = 'ö' buttons[ 2][ 2] = 'p' buttons[ 2][ 3] = 'q' buttons[ 2][ 4] = 'Z' buttons[ 3][ 0] = '5' buttons[ 3][ 1] = 'l' buttons[ 3][ 2] = 'm' buttons[ 3][ 3] = 'n' buttons[ 3][ 4] = 'o' etc Looks OK to me?

Read-Only Author Jon Young Posted 23-Oct-2001 14:32 GMT Toolset C51	RE: accessing array's row 0 Jon Young Did you look in your hex code for '8uüv.' ? Was it there before '7rsşt'? The micro cannot "find" the keys (8, ...). What did it find? Do you get overlay errors when you link?

Read-Only Author Bahri Okuroglu Posted 23-Oct-2001 15:26 GMT Toolset C51	RE: accessing array's row 0 Bahri Okuroglu Jon, Yes, I checked the matrix with debugger and 8uü were there before 7... And, with debugger there was not any problem. It works fine in the debugger.

Read-Only Author Bahri Okuroglu Posted 23-Oct-2001 15:31 GMT Toolset C51	RE: accessing array's row 0 Bahri Okuroglu and, yes there was no compiler/linker warnings. Also, I disabled overlaying using nooverlay flag of the linker.

Read-Only Author Jon Young Posted 24-Oct-2001 13:07 GMT Toolset C51	RE: accessing array's row 0 Jon Young Interesting, can I see the good and bad code?

Read-Only Author Bahri Okuroglu Posted 24-Oct-2001 15:05 GMT Toolset C51	RE: accessing array's row 0 Bahri Okuroglu Jon, I know that it sounds weird. And in fact there is no good code. :) The function may be a bit long to post here, so I can email it to you if you send an email to bahrio at yahoo dot com.

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