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Diffstat (limited to '')
-rw-r--r-- | c/src/exec/score/tools/sh/sci.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/c/src/exec/score/tools/sh/sci.c b/c/src/exec/score/tools/sh/sci.c new file mode 100644 index 0000000000..58be0e68bf --- /dev/null +++ b/c/src/exec/score/tools/sh/sci.c @@ -0,0 +1,157 @@ +/* + * Copyright (c) 1998 Ralf Corsepius (corsepiu@faw.uni-ulm.de) + * + * See the file COPYING for copyright notice. + */ + +#include <math.h> +#include <stdio.h> +#include <stdlib.h> + +#include "sci.h" + +/* + n .. baudrate generator source 0,1,2,3 + + N .. BRR setting (0..255) + + Phi .. processor baud rate + + B .. bitrate + */ + +typedef struct sci_tab { + unsigned int B ; + unsigned int n ; + int N ; + double err ; + } sci_tab_t ; + +static unsigned int bitrate [] = { + 50, + 75, + 110, + 134, + 150, + 200, + 300, + 600, + 1200, + 1800, + 2400, + 4800, + 9600, + 19200, + 38400, + 57600, + 115200, + 230400, + 460800 +}; + +static sci_tab_t test_array[4] ; + +static void Compute( + unsigned int n, + unsigned int B, + unsigned int Phi, + struct sci_tab *entry ) +{ + int a = ( 32 << ( 2 * n ) ) * B ; + + entry->n = n ; + entry->B = B ; + entry->N = rint( ( Phi / a ) - 1.0 ) ; + + if ( ( entry->N > 0 ) && ( entry->N < 256 ) ) + entry->err = + ( ( Phi / ( (entry->N + 1) * a ) - 1.0 ) * 100.0 ); + else + entry->err = 100.0 ; +} + +static sci_tab_t *SelectN( + unsigned int B, + double Phi ) +{ + unsigned int i ; + struct sci_tab* best = NULL ; + + for ( i = 0 ; i < 4 ; i++ ) + { + double err ; + + Compute( i, B, Phi, &test_array[i] ); + err = fabs( test_array[i].err ); + + if ( best ) + { + if ( err < fabs( best->err ) ) + best = &test_array[i] ; + } + else + best = &test_array[i] ; + } + + return best ; +} + +int shgen_gensci( + FILE *file, + double Phi ) /* Processor frequency [Hz] */ +{ + unsigned int i ; + + fprintf( file, + "/*\n * Bitrate table for the serial devices (sci) of the SH at %.3f MHz\n" + " */\n\n", Phi / 1000000.0 ); + fprintf( file, + "/*\n" + " * n .. SMR bits 0,1 : baud rate generator clock source\n" + " * N .. BRR bits 0..7: setting for baud rate generator\n" + " * error .. percentual error to nominal bitrate\n" + " * Hitachi's HW manual recommends bitrates with an error less than 1%%\n" + " * We experienced values less than 2%% to be stable\n" + " */\n\n" ); + fprintf( file, "#include <termios.h>\n\n" ); + fprintf( file, + "static struct sci_bitrate_t {\n" + " unsigned char n ;\n" + " unsigned char N ;\n" + "} _sci_bitrates[] = {\n" + "/* n N error */\n" ); + + for ( i = 0 ; i < sizeof(bitrate)/sizeof(int) ; i++ ) + { + struct sci_tab* best = SelectN( bitrate[i], Phi ); + + if ( i > 0 ) + fprintf( file, ",\n" ); + fprintf( file, " { %1d, %3d } /* %+7.2f%% ; B%d */", + best->n, + best->N, + best->err, + best->B ); + } + + fprintf( file, "\n};\n\n" ); + + fprintf( file, + "int _sci_get_brparms( \n" + " tcflag_t cflag,\n" + " unsigned char *smr,\n" + " unsigned char *brr )\n" + "{\n" + " unsigned int offset ;\n\n" + " offset = ( cflag & ( CBAUD & ~CBAUDEX ) )\n" + " + ( ( cflag & CBAUDEX ) ? B38400 : 0 );\n" + " if ( offset == 0 ) return -1 ;\n" + " offset-- ;\n\n" + " *smr &= ~0x03;\n" + " *smr |= _sci_bitrates[offset].n;\n" + " *brr = _sci_bitrates[offset].N;\n\n" + " return 0;\n" + "}\n" ); + + return 0 ; +} |