diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/jtag/zy1000/zy1000.c | 37 |
1 files changed, 33 insertions, 4 deletions
diff --git a/src/jtag/zy1000/zy1000.c b/src/jtag/zy1000/zy1000.c index 28c65b6e..23f2fdd7 100644 --- a/src/jtag/zy1000/zy1000.c +++ b/src/jtag/zy1000/zy1000.c @@ -1,4 +1,4 @@ -/*************************************************************************** +'n/*************************************************************************** * Copyright (C) 2007-2010 by Øyvind Harboe * * * * This program is free software; you can redistribute it and/or modify * @@ -84,7 +84,33 @@ static int zy1000_khz(int khz, int *jtag_speed) } else { - *jtag_speed = 64000/khz; + int speed; + /* Round speed up to nearest divisor. + * + * E.g. 16000kHz + * (64000 + 15999) / 16000 = 4 + * (4 + 1) / 2 = 2 + * 2 * 2 = 4 + * + * 64000 / 4 = 16000 + * + * E.g. 15999 + * (64000 + 15998) / 15999 = 5 + * (5 + 1) / 2 = 3 + * 3 * 2 = 6 + * + * 64000 / 6 = 10666 + * + */ + speed = (64000 + (khz -1)) / khz; + speed = (speed + 1 ) / 2; + speed *= 2; + if (speed > 8190) + { + /* maximum dividend */ + speed = 8190; + } + *jtag_speed = speed; } return ERROR_OK; } @@ -243,9 +269,12 @@ int zy1000_speed(int speed) return ERROR_INVALID_ARGUMENTS; } - LOG_USER("jtag_speed %d => JTAG clk=%f", speed, 64.0/(float)speed); + int khz; + speed &= ~1; + zy1000_speed_div(speed, &khz); + LOG_USER("jtag_speed %d => JTAG clk=%d kHz", speed, khz); ZY1000_POKE(ZY1000_JTAG_BASE + 0x14, 0x100); - ZY1000_POKE(ZY1000_JTAG_BASE + 0x1c, speed&~1); + ZY1000_POKE(ZY1000_JTAG_BASE + 0x1c, speed); } return ERROR_OK; } |