115 CoE (Microprocessor-based Design)
Electrical and Electronics Engineering Institute
University of the Philippines Diliman
Machine Problem 4: ADC/I2C/UART Interfacing
Objective:
Learn to interface the ADC, I2C and UART of the Z8 microcontroller.
Build a temperature data logger node.
Hardware Components:
1.
2.
3.
4.
Machine Problem 3 capable board
LM35 - Temperature Sensor T092
DS1307 - 64 x8 serial I2C Real Time Clock
3 LEDs (LED1 -Red, LED2 -Yellow, LED3 -Green) -Default: All LEDs are o.
Project Milestones:
Refer to Table 1 for the project milestones with corresponding points.
#
1
2
3
5
Milestone
Display temperature using LCD
Display temperature and save with current time using Flash
Enable communication to a PC
Download time and temperature readings from Flash to PC
Table 1: Project Milestones
Points
35
50*
75
100
Project Schedule:
Activity
Dates
MP4 Release
March 7
Preliminary Checking
March 11
Final Checking + MP3 Release March 18
Table 2: Project Schedule
General Specifications:
a) The idea is to build a standalone temperature data logger. Assume that this will be used and
deployed in remote locations but will need to be connected to a PC to download stored data.
b) Your design should have three modes - data logging mode, data display mode, data transfer
mode.
c) Data log should include the current temperature and the current time (HH:MM:SS) and should be
stored using the microcontroller non-volatile memory. This would mean that the data should still
be present even after the power is shutdown.
d) When the node is powered up, your display should notify the user that it is in data logging mode.
Logging should then continue from the last saved data.
e) When storing data, the red LED should blink for at least half a second and should stay on when
the memory is full.
f) Data should be saved every 10 seconds. Your design should be able to store 12 hours worth of
data.
g) Pressing button A can interrupt logging mode. After button A is pressed, display a message
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asking if the user would like to end logging mode. Set inputs the and outputs so that when 1 is
pressed, logging mode is continued, when 2 is pressed, logging mode is aborted and display
mode is activated. When 3 is pressed, logging mode is aborted and data transfer mode is
activated. When 4 is pressed, the use should be able to set the time. The green LED should light
up when in display mode. The yellow LED should otherwise light up when in data transfer mode.
No LED should light up when setting the time.
h) When in display mode, the user can browse through the data stored by pressing buttons 1, 4,
6 and 8. When buttons 1 and 4 are pressed, the previous set of data is displayed. When
buttons 6 and 8 are pressed, the next set of data is displayed. Note that the temperature should
be displayed with the time when the temperature was logged.
i) Pressing button A can interrupt display mode. Again, a message is displayed asking for a user
choice as in (g).
j) When in data transfer mode, the user has to connect the node to the serial port/usb port of the
computer using a cable. Communication is then negotiated when button B is pressed and data is
transferred to the PC. You can use the PCs hyperterminal application for communication. Note
that you need to format the output to the PC so that it is readily readable by the terminal.
k) Data can be erased by pressing button C for more than 5 seconds. After the 5 second timer
expires, a message is displayed to confirm the erase command. Button C should then be pressed
again to complete the process. A message is again displayed to show the user that erase is
successful. Button A should then be pressed again to resume data logging mode.
l) Your MP will not be checked if you violated any of the project constraints.
Project Grading:
Groups who are able to submit documentation with working demo of the 100% during the
preliminary checking will get a 5% bonus.
Each milestone will be checked.
Your MP will not be checked if you violated any of the project constraints.
Bugs or errors encountered during checking will be given 5% deductions each.
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