HCS08 datasheet(225/290 Pages) MOTOROLA

225 / 290 page

Data Sheet — MC9S08GB60/D V1.5

MOTOROLA

225

MC9S08GB/GT

14.3.1 Mode Control

The ATD has a mode control unit to communicate with the sample and hold (S/H) machine and the SAR

machine when necessary to collect samples and perform conversions. The mode control unit signals the

S/H machine to begin collecting a sample and for the SAR machine to begin receiving a sample. At the

end of the sample period, the S/H machine signals the SAR machine to begin the analog-to-digital

conversion process. The conversion process is terminated when the SAR machine signals the end of

conversion to the mode control unit. For VREFL and VREFH, the SAR machine uses the reference potentials

to set the sampled signal level within itself without relying on the S/H machine to deliver them.

The mode control unit organizes the conversion, specifies the input sample channel, and moves the digital

output data from the SAR register to the result register. The result register consists of a dual-port register.

The SAR register writes data into the register through one port while the module data bus reads data out

of the register through the other port.

14.3.2 Sample and Hold

The S/H machine accepts analog signals and stores them as capacitor charge on a storage node located in

the SAR machine. Only one sample can be held at a time so the S/H machine and the SAR machine can

not run concurrently even though they are independent machines. Figure 14-3 shows the placement of the

various resistors and capacitors.

Figure 14-3 Resistor and Capacitor Placement

When the S/H machine is not sampling, it disables its own internal clocks.The input analog signals are

unipolar. The signals must fall within the potential range of VSSAD to VDDAD. The S/H machine is not

required to perform special conversions (i.e., convert VREFL and VREFH).

RAIN1

RAS

CAS

CAIN

RAIN2

RAIN3

RAINn

ATD SAR

ENGINE

CHANNEL

SELECT 0

CHANNEL

SELECT 1

CHANNEL

SELECT 2

CHANNEL

SELECT n

INPUT PIN

–

VAIN

HCS08 bảng dữ liệu(PDF) 225 Page - Motorola, Inc

HCS08 bảng dữ liệu(HTML) 225 Page - Motorola, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

bảng dữ liệu tải về

Link URL