RS08KA2 PROMO Freescale Semiconductor, RS08KA2 PROMO Datasheet - Page 24

• Manufacturer Part Number: RS08KA2 PROMO
• Description: DEMO KIT, SILICON BUNDLE, RS08KA2
• Manufacturer: Freescale Semiconductor

Specifications of RS08KA2 PROMO

• Kit Contents: DEMO9RS08KA2 Board, USB Cable, Quick Start Guide, User Manual, Packing List
• Svhc: No SVHC (15-Dec-2010)
• Development Tool Type: Demonstration Kit
• Kit Features: RS08KA2 Microcontroller,
• Silicon Manufacturer: Freescale
• Core Architecture: RS08
• Core Sub-architecture: RS08
• Silicon Core Number: MC9RS08
• Silicon Family Name: RS08KA
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Emulated ADC Application Example
24
4. Define bus frequency. There is software overhead to enable the timer and the comparator before
5. RS08 coding. The software code can be divided into four parts: declaration, initialization, ADC
The lookup table that converts the timer count to linear ADC code is shown in
taking measurements. To avoid software latency error, it is recommended to choose a bus
frequency which is at least five times the timer clock frequency. In this example, a 2MHz bus
frequency is initially chosen, then timer prescaler is set to divide-by-8 option which gives 250kHz
timer clock frequency, i.e. 4µs resolution. In applications where the choice of bus frequency cannot
be chosen freely, the lookup table can be rebuilt to compensate for the software latency.
read, and table lookup.
a) First, declare the variables required and the lookup table location. The most frequently used
variables should be allocated on the tiny addressable RAM area, i.e. $0000 to $000D, such that
the single byte tiny/short instructions can be used for data manipulation. Hence, code density
is greatly improved. Lookup table is located in the upper memory, there is no restriction on
where to put the table, in this example $3E00 is arbitrarily chosen. All upper memory access is
done through the 64-byte paging window located on the first page.
Time (µs)
1012
1016
1020
12
16
20
0
4
8
Code
Table 2-7. Non-Linearity Compensation Lookup Table
=
⎧
⎪
⎪
⎪
⎨
⎪
⎪
⎪
⎩
⎛
⎜
⎜
⎝
ADCin
---------------------------------- -
ADC Input (V)
(Equation
Getting Started with RS08, Rev. 1
Step
0.09
0.18
0.26
0.35
0.43
4.95
4.95
4.95
0
–
0
Step
---------- -
2
2)
and so on...
⎞
⎟
⎟
⎠
+
1
Timer Count
253
254
255
;
;
0
1
2
3
4
5
⎛
⎝
⎛
⎝
ADCin
ADCin
≥
<
Step
---------- -
Step
---------- -
2
2
Linear ADC Code
(Equation
⎞
⎠
⎞
⎠
253
253
253
10
14
18
23
0
5
5)
Freescale Semiconductor
Table
2-7.
Eqn. -5