  Monolithic active pixel sensors (MAPS) are now well established as a
technology for tracking charged particles, especially when low material budget
is desirable. For such applications, sensors focus on spatial resolution and
pixels with digital output or modest charge measurement ability are well
suited. Within the European Union STRONG-2020 project, which focuses on
experiments using hadrons, the TIIMM (Tracking and Ions Identifications with
Minimal Material budget) joint research activity intends to expand granular
MAPS capacity to energy-loss ({\Delta}E) measurement for ion species
identification. The TIIMM prototypes are developed in the Tower Jazz 180 nm
CMOS image sensor (CIS) process. The Time-Over-Threshold (ToT) method is
applied to the sensor for the energy-loss measurement. The main design details
and the preliminary test results from laboratory measurements of the initial
TIIMM prototype are presented in this work.
