The LPC2114FBD64,151: At 60 MHz the ARM7 core can sustain a few hundred MIPS — enough to run a Modbus RTU stack, a PID loop, and a simple UI without a co-processor. The 16 KB SRAM is tight for heavy buffering; if your application queues Ethernet frames or logs large datasets, you will need external RAM or a part with more on-chip memory. The 128 KB Flash is adequate for a single firmware image with a modest bootloader, but leaves no room for a full OTA update staging area.
NXP has marked the LPC2114FBD64 as Obsolete. No further factory orders are accepted, and no last-time-buy window remains open. For a production board that already carries this MCU, the only sourcing path is the independent surplus and broker channel.