Z8FS040 Datasheet, PDF (31/56 Pages) Zilog, Inc. – ZMOTION Detection and Control Family Featuring Zilog’s PIR Technology

ZMOTION^TM Detection and Control Family
Product Specification
ANAx Scan Request
Analog Channel 0, 1, 3-7 Scan Requested Bits
Set by Application; cleared by PIR engine
These bits allow the user application to request the Engine to perform an A/D conversion on the non-
reserved analog inputs. When requested, the Engine will reconfigure the appropriate I/O pin to a single-
ended, unbuffered input using a 2 Volt reference. It will then take the next sample and store it in the PIR
ADC Result Value Registers and clear all ANAx Scan Request bits. The I/O configuration for the ANAx
pin is not returned to its previous configuration by the Engine. If needed, the user application must do
this.
If multiple request bits are set simultaneously, the Engine will only scan the lowest numbered ADC
channel requested and ignore any other requests. The user application should set one request bit then
poll it to determine when the conversion is complete and the data is ready.
When ADC Scan requests are being serviced by the PIR engine, ADC conversions on the PIR sensor
are suspended. Therefore the user application should be careful not to continuously request ADC
Scan’s. The Process Rate Register in the “Advanced PIR Engine” section can be monitored to ensure
the Engine is receiving enough time to perform its required PIR Sensor ADC scans.
0 = no conversion requested/last conversion completed
1 = perform a conversion on this channel
PIR ADC Result Value (ePIR_ADC_Result)
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Field
Control
ADC Result Value
Read
Address
10AH
10BH
PIR ADC Result Value (Bits 0-15)
ADC Scan Request Result Value
Controlled by PIR engine
The PIR ADC Result Value contains the result of the last application requested ADC conversion.
The data format is identical to that given in the Z8 Encore XP Product Specification (PS0228) for
registers ADCD_H and ADCD_L.
Example for requesting an ANA0 Conversion:
o Set bit 0 (ANA0 Scan Request) in PIR Status/Control Register 3 (ePIR_SC3)
o Wait until the ANA0 Scan Request bit is cleared by the Engine
o Read the ADC conversion result from the PIR ADC Result Value register
Note: Even though the ADC Result Value is a 16 bit register, atomic operations are not required since
the value is only updated at the request of the application.
PS028506-1110
PRELIMINARY
26