 |
| Schematic: Simple Spin Board |
SIMPLE SPIN BOARD
PART 2: Updated schematic, more simple software, 1st circuit to run at low power
If you missed Part 1 of the Propeller Simple Spin Board, find it at this link:
Propeller Simple Spin Board
Propeller Simple Spin Board
A More Simple Program
Here's a program with 5 statements instead of 7 to blink the LED on pin 15. Later we will show a program with only 4 steps in Spin.
FIRST MOD DISABLING THE BROWNOUT DETECTOR
In this first modification to the Propeller Simple Spin Board, the connection from BOEn to Ground is removed. Insert a new connection between BOEn and Vdd. This will disable the brownout detector by connecting it to high, and prevent the board from resetting at 2.7 volts or less. (not shown on schematic)
I can't seem to disable brown out detection, if I connect BOEn to Vdd even at 3.3v the Prop won't do anything.
Put an external pullup on RST (a 220 ohm resistor from RST to VDD).
When BOE Brown Out Enable is grounded, the Propeller chip has an internal pullup activated. When BOE is held high, the internal pullup is not active, and an external pullup is required on RST to restore functioning.
VOLTAGES
I can't seem to disable brown out detection, if I connect BOEn to Vdd even at 3.3v the Prop won't do anything.
Put an external pullup on RST (a 220 ohm resistor from RST to VDD).
When BOE Brown Out Enable is grounded, the Propeller chip has an internal pullup activated. When BOE is held high, the internal pullup is not active, and an external pullup is required on RST to restore functioning.
VOLTAGES
The Propeller Simple Spin Board is capable of operations at voltages much lower than 3.3, 3.0 or 2.7 volts and disabling the brownout detector BOEn will make this possible. This will allow longer battery operations as the voltage drops down, and running on tiny pen cells, watch batteries and other low power sources. How low can you go below 2.7 volts? This is left as a student exercise. A new schematic will reflect this change. For more information
http://tymkrs.tumblr.com/post/116554...pins-explained
Q&A Section
A - Put an external 220 ohm resistor pullup from RST to VDD. When BOE Brown Out Enable is grounded, the Propeller chip has an internal pullup activated. When BOE is held high, the internal pullup is not active, and an external pullup is required on RST to restore functioning.
Q&A Section
A - Put an external 220 ohm resistor pullup from RST to VDD. When BOE Brown Out Enable is grounded, the Propeller chip has an internal pullup activated. When BOE is held high, the internal pullup is not active, and an external pullup is required on RST to restore functioning.