This blog post is about our current EV3 robot we're planning to use in the 2023/2024 FLL competition. Some features: 2 large motors for steering. 2 medium motors for attachments. 2 colour sensors for picking up the white and black lines, also used for line squaring. 1 gyro sensor. To enable attachments to be changed as quickly as possible we're using gravity to keep the gears connected, i.e. you don't need to fasten anything to the robot. Every attachment has 2x 12 tooth double bevel gear (part 32270) which comes in contact with the 2x 20 tooth double bevel gears (part 32269) on the robot. The medium motors are horizontally aligned on the robots, but we use 12 tooth double bevel gears to convert that to vertical alignments. These in turn are connected to 20 tooth double bevel gears, and the attachments in turn connect to these 20 tooth double bevel gears with their 12 tooth double bevel gears. The complete robot is modelled in Bricklink Studio 2 . You can download the rob
Compare this schematic to the 8051 schematic posted earlier. U6 (2764 8kb ROM chip) was replaced with a 6264 8kB SRAM chip. The idea is that the 8051 will still be able to access this chip as an external ROM chip using PSEN#, but also as external RAM. This way it is possible to download firmware to SRAM and execute the firmware as if it was stored on ROM. Comparing the DIP pinouts between SRAM (6264 8kb SRAM) and ROM (2764 8kB ROM), we can see that the two chips follow more or less the same pin layout, except for the address pins: Pin SRAM ROM 1 N/C Vpp 2 A4 A12 3 A5 A7 4 A6 A6 5 A7 A5 6 A8 A4 7 A9 A3 8 A10 A2 9 A11 A1 10 A12 A0 11 D0 D0 12 D1 D1 13 D2 D2 14 Gnd Gnd 15 D3 D3 16 D4 D4 17 D5 D5 18 D6 D6 19 D7 D7 20 CE1# CE# 21 A0 A10 22 RD# G# 23 A1 A11 24 A2 A9 25 A3 A8 26 CE2 N/C 27 WR# P# 28 Vcc Vcc To enable the SRAM to respond to ROM access and RAM access, we need to add logic to the chip select and output enable pins. Chip select (CE1# and CE2): The SRAM should be selected either