approximation analog-to-digital convertor that supports up to ten bits of resolution. While the MC68HC16Z1CAG16 has the correct type of ADC, we need sixteen bits of resolution in order for our temperature ranges to be between 30.0°C and 1400.0°C and we do not want to oversample to get sixteen bits of resolution. Thus, having a ten bit successive approximation ADC is a nonfactor for this microcontroller. Since this microcontroller does not have any built it graphics drivers, we needed to design the protocol that drove the display. We are going to interface with displays that support SPI, so no additional hardware was be required to communicate between this microcontroller and the display. If a four-wire touch screen is not used, we required a set of four direction buttons (^, V, <, >) to serve as the user controls for the microcontroller. Comparison Below in a Table 2 there is a summary of the features that are relevant to our temperature controller. Candidate MSP430F449 Package LQFP TQFP SPDIP QFP Number of Pins 100 44 28 144 Number of I/O Pins 48 35 21 16 SRAM (Kbye) 2 8 32 1 Program Memory (Kbyte) 60 (Shared) 128 128 None Data Memory (Kbyte) 60 (Shared) None Shared with Program Memory None UART 2 (Shared) 2 2 2 SPI Lines 2 (Shared) 2 2 1 USB Support None None None None RS-232 Support None None None None Ethernet Support None None None None Cost (1) $10.67 $5.43 $3.57 $11.37 Table : Comparing Features of Various Microcontrollers The above table summarizes the main features available from our different candidates. Our main point of comparison is the amount of onboard memory, both SRAM and EEPROM, and the peripheral support on the microcontroller. We remain flexible with the package sizes, but we do prefer PLCC, SPDIP, then TQFP, then QFN. We also want to minimize the number of pins on the microcontroller. In terms of memory, the PIC24FJ256DA206 has the most, with respect to program memory and SRAM. This allows us to be extremely flexible in 6 B
has a font tool which is extremely useful because we can design our own text and have this displayed on the screen. This display needs 5V to power the whole system which is more than the other displays but this won’t be an issue because some of our other components need 5V also. The display has a viewing area of 47.87 x 63.84mm and the whole module itself has dimensions of 56.0 x 77.7 x 11.4mm. One concern we might have with this display is that it is manufactured in Australia and there might be issues getting it fast if something happens. We are going to continue to look for US vendors which would be the best option for us. Figure : 4D Systems uLCD-32PT (GFX) Comparison Candidate uLCD-32PT (GFX) Dislpay Type TFT TFT TFT TFT Type of 4-Wire Resistive 4-Wire Resistive 4-Wire Resistive 4-Wire Resistive Num. of Pixels (Width) 320 480 320 320 Num. of Pixels (Height) 240 272 240 240 Diagonal Dimension 3.5 in 4.3 in 3.5 in 3.2 in Overall Module Dimensions 3.47”x2.64” 4.15”x2.65” 3.02”x2.51” 3.06”x2.20” Graphics Controller Yes Solomon SSD2119 No No Yes PICASO-GFX Integrated LED Driver No Yes Orise OTA5180A Yes Novatek NT39016D Yes PICASO-GFX Interface SPI or parallel 24-bit RGB 24-bit RGB 5 pin serial Viewing Angle 12:00 6:00 o’clock 12:00 o’clock 12:00 Typical Logic Supply Voltage +3.0V +3.3V +3.3V +5.0 Min. Operating Temp. -20°C -20°C -10°C -20°C
Figure Schematic Design 126 Figure 60-Master Schematic Design 126 Figure PCB Design 127 Figure 62-Chassis Design 127 Works Cited LS200 – Power Supply Datasheet PTN78000A – Switching Regulator Datasheet PTR08060W – Switching Regulator Datasheet LT1129-3/LT1129-5 – Switching Regulator Datasheet Chassis, Heater Display Research Newhaven 4.3” Display Data OTA5180A Data Sheet Graphics Controllers Texas Instruments Parts