Question 4 a) You have been asked to design an embedded system with PIC16F873A to monitor body temperature of patient continuously by a biomedical temperature sensor connected at RAO and activate an active-high alarm connected at RB7 only when the temperature reaches a critical level. Write an assembly program for the application if the biomedical temperature sensor generates 4-bit digital signal to the upper four bits of a file register. Assume that the file register is labelled as REG1 and the alarm will only be activated when the digital output is equal to decimal 10. (10 marks) Given that the biomedical temperature sensor stated in the Q4(a) is replaced with a new sensor that generates 40mV/C. The alarm will only be activated when the temperature value exceed 40C. The PIC16F873A is supplied with 5 V and configured with only three analogue inputs. The voltage reference of the ADC is taken from the supply voltage and ground. The internal ADC RC oscillator is used as the clock source of the ADC to provide typical bit conversion time of 4 us. The 8-bit, left-justified ADC output result is used for the program. i) Determine the ADC output value when the temperature sensor detects 40C. (3 marks) ii) Rewrite the assembly program written in Q4(a) for the application with new sensor. You do not need to use the ADC interrupt feature. Assume that DELAY_50us delay subroutine that generates 50 us delay is given. (12 marks) [Total: 25 marks) Question 4 a) You have been asked to design an embedded system with PIC16F873A to monitor body temperature of patient continuously by a biomedical temperature sensor connected at RAO and activate an active-high alarm connected at RB7 only when the temperature reaches a critical level. Write an assembly program for the application if the biomedical temperature sensor generates 4-bit digital signal to the upper four bits of a file register. Assume that the file register is labelled as REG1 and the alarm will only be activated when the digital output is equal to decimal 10. (10 marks) Given that the biomedical temperature sensor stated in the Q4(a) is replaced with a new sensor that generates 40mV/C. The alarm will only be activated when the temperature value exceed 40C. The PIC16F873A is supplied with 5 V and configured with only three analogue inputs. The voltage reference of the ADC is taken from the supply voltage and ground. The internal ADC RC oscillator is used as the clock source of the ADC to provide typical bit conversion time of 4 us. The 8-bit, left-justified ADC output result is used for the program. i) Determine the ADC output value when the temperature sensor detects 40C. (3 marks) ii) Rewrite the assembly program written in Q4(a) for the application with new sensor. You do not need to use the ADC interrupt feature. Assume that DELAY_50us delay subroutine that generates 50 us delay is given. (12 marks) [Total: 25 marks)