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BoydNielsen
Joined: 20 Aug 2006
Posts: 12
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| Byte to Nibble |
 Posted: Sun Oct 05, 2008 4:08 pm |
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Does anyone have a quick and efficient way of converting a byte into two separate nibbles in CCS? Years ago on a different platform, we used to be able to:
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int8 a, MSnibble, LSnibble;
a = 174; // arbitrary number
MSnibble = a / 16; // 'MSnibble' is the upper nibble
LSnibble = a mod 16; // 'mod' for modulus
// 'LSnibble' is the lower nibble
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However, this does not seem to work in CCS. A code snipet would be extremely helpful.
Boyd |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Oct 05, 2008 4:21 pm |
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Look at the lcd_send_byte() function in the CCS lcd.c driver.
It passes nibbles to another function and it shows how to do it. |
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BoydNielsen
Joined: 20 Aug 2006
Posts: 12
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| Posted: Sun Oct 05, 2008 4:33 pm |
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Thanks. Sometimes one forgets the basics (shift right and bit masking)!
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a = 174;
MSnibble = a >> 4; // right shift to remove lower nibble
LSnibble = a & 0xF; // bit mask to remove upper nibble
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Boyd |
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Ttelmah
Guest
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| Posted: Mon Oct 06, 2008 3:12 am |
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As a comment, the original would have worked, if you had used the C modulus function (%, not 'mod'). Shifts are much quicker though. However the compiler is 'smart' enough, to perform division by 16, using shifts, so it would not make too much difference. 
Best Wishes |
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