Sub-Block Description
MOTOROLA
Universal Asynchronous Receiver/Transmitters (UART) Modules
27-15
Example:
Integer Division ÷ 2
Reference Frequency = 19.44 MHz
NUM = 0x0000
DENOM = 0x0001
UBIR = NUM - 1
UBMR = DENOM - 1
NOTE:
Notice each value written to the registers is one less than the actual value.
Example:
Non-integer Division
Reference Frequency = 16 MHz
Output Frequency = 920 kbps
× 16 (sampling) = 14.72 MHz
Ratio --> 14.72 ÷ 16 = 0.92
NUM = 92 (decimal) = 0x5C
DENOM = 100 (decimal) = 0x64
UBIR = NUM - 1
UBMR = DENOM - 1
NOTE:
The ratio is derived directly from the division with no factoring (easiest).
To derive the exact ratio, some factoring must be performed. Factoring the
above ratio produces:
Factored Ratio: 23 ÷ 25
NUM = 22 (decimal) = 0x0016
DENOM = 25 (decimal) = 0x0019
Example:
Non-integer Division
Reference Frequency = 25 MHz
Output Frequency = 920 kbps × 16 (sampling) = 14.72 MHz
Ratio --> 14.72 ÷ 25 = 0.5888
NUM = 5888 (decimal) = 0x1700
DENOM = 10000 (decimal) = 0x2710
UBIR = NUM - 1
UBMR = DENOM - 1
NOTE:
The ratio is derived directly from the division with no factoring (easiest).
To derive the exact ratio, some factoring must be performed. Factoring the
above ratio produces:
Factored Ratio = 184 ÷ 313
NUM = 183 (decimal) = 0x00B7
DENOM = 313 (decimal) = 0x0139
Example:
Non-integer Division:
Reference Frequency: 30 MHz
Output Frequency: 920 kbps × 16 (sampling) = 14.72 MHz
Ratio --> 14.72 ÷ 30 = 0.4907
NUM = 4907 (decimal) = 0x132B
DENOM = 10000 (decimal) = 0x2710
NOTE:
The ratio is derived directly from the division with no factoring (easiest).
To derive the exact ratio, some factoring must be perform. Factoring the
above ratio produces:
Summary of Contents for DragonBall MC9328MX1
Page 68: ...1 12 MC9328MX1 Reference Manual MOTOROLA Introduction ...
Page 86: ...2 18 MC9328MX1 Reference Manual MOTOROLA Signal Descriptions and Pin Assignments ...
Page 116: ...3 30 MC9328MX1 Reference Manual MOTOROLA Memory Map ...
Page 126: ...4 10 MC9328MX1 Reference Manual MOTOROLA ARM920T Processor ...
Page 160: ...8 8 MC9328MX1 Reference Manual MOTOROLA System Control ...
Page 272: ...13 32 MC9328MX1 Reference Manual MOTOROLA DMA Controller ...
Page 281: ...Programming Model MOTOROLA Watchdog Timer Module 14 9 ...
Page 282: ...14 10 MC9328MX1 Reference Manual MOTOROLA Watchdog Timer Module ...
Page 300: ...15 18 MC9328MX1 Reference Manual MOTOROLA Analog Signal Processor ASP ...
Page 438: ...18 16 MC9328MX1 Reference Manual MOTOROLA Serial Peripheral Interface Modules SPI 1 and SPI 2 ...
Page 478: ...19 40 MC9328MX1 Reference Manual MOTOROLA LCD Controller ...
Page 574: ...21 32 MC9328MX1 Reference Manual MOTOROLA Memory Stick Host Controller MSHC Module ...
Page 598: ...23 16 MC9328MX1 Reference Manual MOTOROLA Real Time Clock RTC ...
Page 670: ...24 72 MC9328MX1 Reference Manual MOTOROLA SDRAM Memory Controller ...
Page 726: ...25 56 MC9328MX1 Reference Manual MOTOROLA SmartCard Interface Module SIM ...
Page 736: ...26 10 MC9328MX1 Reference Manual MOTOROLA General Purpose Timers ...
Page 854: ...29 18 MC9328MX1 Reference Manual MOTOROLA I2C Module ...
Page 900: ...30 46 MC9328MX1 Reference Manual MOTOROLA Synchronous Serial Interface SSI ...
Page 942: ...32 26 MC9328MX1 Reference Manual MOTOROLA GPIO Module and I O Multiplexer IOMUX ...